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Swap File Optimizations? 177

Posted by Cliff
from the coaxing-out-more-speed-via-organization dept.
fastswap asks: "I've got a pretty standard computer with reasonably fast drives. I've got an old 2GB-but-fast drive, and a spare channel on the motherboard. Does it make sense to install the 2GB drive on its own controller and use it for a dedicated, fixed swap file? I figure if the computer's using the swap file, then in the current setup with the swap file on the primary controller, then it's contributing to hard drive thrash exactly when one doesn't want it to (i.e. when the machine needs the swap file). If it is better to have a dedicated swap file on its own controller, is the same true for other operating systems with similar approaches to virtual memory? Since drive space is so cheap now, should the swap file be fixed size anyway rather than letting Windows suddenly get the urge to resize the thing?"
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Swap File Optimizations?

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  • Erm (Score:2, Funny)

    by Anonymous Coward
    Swap file? Modern operating systems use a page file. Get out of your Loonix mind set, hippie.
    • ...is that MS Windows is not a modern operating system. It got a shot in the arm as a reincarnated MICA (VMS 5+) but Microsoft managed to hobble even that.

      Swap partitions are even faster, but MS Windows can't do those.
  • swapping? (Score:4, Interesting)

    by ArmorFiend (151674) on Wednesday March 24, 2004 @02:39AM (#8653553) Homepage Journal
    Do people still swap? Seriously, I can't remember when I heard my prime dueller do the rumble, and its only got 512 megs of ram.
    • Re:swapping? (Score:4, Informative)

      by Hythlodaeus (411441) on Wednesday March 24, 2004 @02:48AM (#8653585)
      As is often the case, games are making some of the greatest demands on hardware. Many current games fill 300 or more MB by themselves, and right now I'm sitting on 225 MB with Mozilla, Word, and mIRC open.
      • if you start working on Java development and if you have quite a lot of files to compile... Welcome to the world of blinking disk lights...
      • by ColaMan (37550) on Wednesday March 24, 2004 @05:27AM (#8654119) Homepage Journal
        Close Word and you'll probably gain 100MB :-)
        No, seriously.
        I don't know what the hell kinda easter egg's in Word - I know Excel had a flight sim , maybe Word's got a 5 minute video of BillG rolling naked in a pile of money and whores.
        • The first big bloat egg I heard of was
          Bill's horse pic in win95. From which we
          can reliably conclude that he prefers horse
          to whores, although the statement is
          misleading in some ways.

        • You don't seem to have much of a clue. Modern programs do not load entirely into RAM. Instead, only the portions of the program that are actually needed are loaded into RAM. So if you aren't using the spell check feature, it won't cost you any RAM, just disk space. This is done primarily with DLLs / shared libraries, but the paging system of most modern OSes is lazy -- even for the base program, it only loads what is needed.

          So assuming there were something as large as a 100 MB Easter egg, it wouldn't take
          • I have plenty of clue and I'm fully aware of DLL's/shared libraries and all the jazz that modern OS's do. Please note, however, the whole "BillG naked, pile of money and whores" thing. That *was* an attempt at humour - and who lets the mere truth get in the way of a good joke these days, hey?
      • Add to games data mining and modelling software, plus the databases and the database software itself. Full resolution video capturing always roasts your system nicely too.
    • I'd say that you don't do anything worthwhile with that computer, then...but hey, that's just me.
    • Even if you have enough ram to function without swap space, you should enable it and give it some room so that the OS can swap out as it sees fit to make room for a bigger disk cache.
    • Up until 2 days ago my office PC was swapping loads, then again it was a PIII 800 with 256 meg of memory. It was leading to performance problems. My new P4 2.8Ghz with a gig of ram doesn't seem to have the same issues :-) Now I'm just trying to get top to report that it is 0% idle, used to happen a lot on the old machine.

      Yes this post was just an excuse to tell people that I have a new computer :-)


    • Yes, swap is still important to many people, even those with 512MB of RAM or more. With a dozen xterms, Mozilla, OpenOffice, etc. open, starting something like a MCAD application makes swap very very useful (if the OS is efficient about it, that is). Using swap doesn't necessarily mean slow performance, if the OS does a one-time dump of unused pages to the disk allowing the one big app to take what it needs. Switching among several large apps, though, means a purchase order for more RAM is in order.
    • Re:swapping? (Score:2, Interesting)

      by jonadab (583620)
      > I can't remember when I heard my prime dueller do the rumble, and its only
      > got 512 megs of ram.

      I make it a point to have enough RAM that the system almost never has to use
      the swap space, but I consider it vital to have the swap space there as a
      safety net, because occasionally something uses a whole lot of RAM (e.g., I
      might write a quick-and-dirty use-once-and-throw-away Perl script to process
      some data, and it might store them in a Really Big Hash while doing so, or I
      might have to work with an imag
  • Fixed size... (Score:5, Interesting)

    by Motherfucking Shit (636021) on Wednesday March 24, 2004 @02:43AM (#8653571) Journal
    The general advice that I've picked up is that, at least in the *n?x world, you should create a swap partition which is double the size of the machine's physical RAM. For example, if you're sitting on 512MB of RAM, a 1GB swap partition is appropriate.

    You only mention Windows towards the end of your question so I can't tell whether or not you're looking for a Windows answer. I've always allowed Windows to resize its swap file, but within a small window. This machine (Win2K) has 640 megs of physical RAM, and the swap file is set at 1280 minimum, 1960 maximum; that gives Windows "double the real RAM," but not a license to take over the whole drive. Seems to work well for me.

    I've never tried putting the swap on its own channel or controller - or even on its own drive - under any OS. Like you, I'd be interested in hearing whether or not this is worth the trouble.
    • Re:Fixed size... (Score:3, Informative)

      by zatz (37585)
      I think the recommendation of "at least twice physical memory" makes sense only with a VM system which employs a one-to-one mapping between allocated pages and disk blocks. I do not believe either Linux or Windows works this way.
      • Re:Fixed size... (Score:3, Informative)

        by Just Some Guy (3352)
        FreeBSD, on the other hand, explicitly recommends having at least twice as much swap as real memory. From tuning(7):
        The kernel's VM paging algorithms are tuned to perform best when there is at least 2x swap versus main memory. Configuring too little swap can lead to inefficiencies in the VM page scanning code as well as create issues later on if you add more memory to your machine.
      • The last umpteen Linux installs I performed had this "twice physical RAM" suggestion for swap. Has the VM changed in the last year?

        And a real question: what do you do when you subsequently add more RAM?

    • Re:Fixed size... (Score:3, Informative)

      by Brandybuck (704397)
      I've never tried putting the swap on its own channel or controller - or even on its own drive - under any OS. Like you, I'd be interested in hearing whether or not this is worth the trouble.

      I still do this, but with 1G of RAM, I never swap anymore. Back back when I had a 100MHz system and 32M RAM, putting the swap on another harddrive made a significant difference. That was with Linux. Since Windows uses a swap file instead of a raw partition, so it might not make much of a difference.
    • Re:Fixed size... (Score:3, Informative)

      by WSSA (27914)
      Don't let Windows resize the swapfile - that's a surefire path to fragmentation, fragmentation = slowness.
      • Well, I can't disagree with that. However, I would imagine that the OP and anyone savvy enough to be similarly curious is probably the type who runs chkdsk /r and defragments fairly often. At least I do ;)
      • Absolutely. Fixed size at twice the amount of RAM, on a separate disk if possible. It's worked for me since NT4 (through 2K, XP, and server 2003). It's the resizing that really thrashes your disk anyway. Cheers

        1
    • 2*physical RAM is an old rule of thumb which falls over on large systems; we have one server with 16GB of RAM and we don't really want to allocate 32GB of swap space which should never be used as a rule.

      In most cases, servers should never swap; most systems these days only have swap as a space for crash dumps; both Solaris and Windows do this.

      Also, as others have said, leave Windows page files at a constant side to avoid fragmentation; this is one thing which the *nix world has definately got right.

    • That was valid in the old BSD days, but newer paging algorythms no longer need this.
    • A lot of people here have repeated the old advice to make swap twice your RAM. OK, so in the days of 16Meg RAM that would mean 32Meg of swap, for a total of 48Meg. So why would a 64Meg machine need any swap?

      I'm not flaming or trolling, I'm serious. Even if running a GUI (which never happened in the days of 16Meg machines, and don't mention X Windows because I know for a fact the serious number cruning workstations didn't waste their precious RAM on X -- remember, we're talking "back in the day" here) even i

      • Why should one not swap out program and data structures that one is not using, and free up ram for high-turnover uses such as disk caching? Given that disk space is cheap and the page swapping system exists, you might as well make use of it. I agree that, if one were developing a new OS with todays hardware, it is arguable that you shouldn't bother with a swapping mechanism (though the inifinite ability of people to use up processor power makes me doubt this). But since we have the swapping mechanism, you c
        • But I'm not making use of it. It's my understanding (correct me if I'm wrong) that the Operating System is what makes use of it, when needed. So far I haven't seen it used (as reported by swapctl [openbsd.org]). Wolfrider [slashdot.org] reports [slashdot.org] similar findings (in thread above).
    • The only problem with this (which doesn't make much sense in my mind) and as a caveat, I would say for "modern OSs", why would you need to double the amount of swap for more RAM you put in the system? You'd think that you would need to use a decreasing amount of swap with the more memory you put in your system?

      The only thing I could possible figure out, is that if ALL your RAM dumps all of its memory to the swap at once; but again, what OS does this, I'm quite sure that Linux (modern) doesn't do this, a

    • A technique we Windows users have suggested for years has been to set the minimum and maximum swapfile/pagefile size to the same value equal to twice the amount of real RAM you have. Back under Windows 3.11 we had to type in the settings in our Windows configs. This technique has stuck really only out of habit though. At one time the formula was 2.5 x RAM. You can probably go lower. On Linux I used a swap filesystem equal in size to my real RAM, and I had no problems.

      I've always found storing Swap/pagefi
    • --You shouldn't follow such advice blindly, without monitoring how much swap actually gets USED... Otherwise that 1GB of disk is completely wasted.

      --Example: 900MHz AMD Duron, 512MB RAM
      swapon -s
      Filename Type Size Used Priority
      /dev/hda5 partition 257000 0 3
      /dev/hdb5 partition 514040 0 3

      free

      total used free shared buffers cached
      Mem: 516196 232612 283584 0 24876 85448
      -/+ buffers/cache: 122288
  • Dedicated (Score:2, Informative)

    by yosemite (6592)
    It is better
  • by viware (680138) on Wednesday March 24, 2004 @02:49AM (#8653591)
    My experience has always been to give windows a fixed page file, at twice the RAM size (ie. 512MB RAM so 1024MB page file). Further, a separate physical drive is the best scenario, or second best is a separate partition.

    It is important to note that WindowsXP will use the page file whether you've got plenty of RAM or not.
    • I've never understood the reasoning behind "I have more ram, so I make a bigger swap file".

      Seems counterintuitive. Does anyone know why this is ??
      • Well, back in the good old days when 4MB was "more RAM", you generally only had a machine with relatively large amounts of RAM if you were processing a similarly large amount of data.

        Joe User would have a machine with 4MB RAM and 8MB swap for his word processing and Ultima 2 or whatever.

        Stan Scientific would have a machine with 32MB RAM and 64MB swap because he probably was going to eventually have to deal with datasets larger than 32MB (if you've done ANY scientific computing over historical datasets, yo
      • Psychology, you have a faster computer, that can do more tasks, and you can multitask, so you will run larger tasks that take more ram, and that swap WILL be used.

        The other reason is that you have some recurring processes(scheduled tasks, crons, disk defrags) that run at times when the machine is supposed to be idle, but may just be busy. With larger swap, you avoid a crash, by risking more swapin/swapouts.
    • by Quarters (18322) on Wednesday March 24, 2004 @10:20AM (#8655548)
      It is important to note that WindowsXP will use the page file whether you've got plenty of RAM or not.

      You can instruct XP (and probably 2K) to not page the executive and to use more memory as cache space. This reduces the amount of paging significantly.

      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Session Manager\Memory Management
      *Change DisablePagingExecutive to 1
      *Change LargeSystemCache to 1
      *Reboot

      • You can instruct XP (and probably 2K) to not page the executive and to use more memory as cache space. This reduces the amount of paging significantly.
        HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contr o l\Session Manager\Memory Management
        *Change DisablePagingExecutive to 1
        *Change LargeSystemCache to 1
        *Reboot

        True, but doing this disables standby and hibernate modes, since the kernel can't be unloaded any more. If that's not a problem for you, go ahead of course, but it's worth being aware. I did t
  • by derrith (600195) on Wednesday March 24, 2004 @02:50AM (#8653592)
    I've done this under linux, say get a 2-6GB drive and use it as dedicated swap. I tend to do this with scsi servers when I'm patching together old gear. Say an 18GB root drive and then the smaller drive as dedicated swap. leaves everything open. And if the swap drive does get thrashed, no big deal. It's quite effective and works well in my experience.
  • by Anonymous Coward
    Dedicated is better.

    However, you will never get true swap performance using Windows.

    To do that you need a real operating system. Linux will let you put one swap partition on each controller, set them to the same priority, and it will automatically spread the access between them, getting a RAID-like speedup in your swap access times.

    Also, remember to put swap partitions (if you are using files you are hopelessly fucked) on the end of the disk, so that they will be on the outer sectors where the transfer
    • but putting them in the middle of the disk will on average reduce the seek time.
      • only if your files are spread evenly throughout the entire disk. I know most of MY disks are only using 2-3 GB of the 40-80 available.

        The exception is the 'storage' drive on the server, and that's only holding files, not serving as a swapper or system volume.

        I've had the best luck in 2.6 with using a swapfile instead of a partition, and making the swapfile with 'dd' and 'mkswap' after the base system is installed and before I lay down all the other stuff. That places the swapfile close to the most-used ap
        • That places the swapfile close to the most-used application files and towards the outer end of the disk.

          How do you know? One of the features of ext2/3 is the way it avoids fragmentation by randomly placing files all over the partition, unlike FAT16/32 which fills the partition from start to end.

          The only way to optimize the location of swap space in Linux is to use a dedicated swap drive, or place the swap partition between /boot and /.
          • to some extent, yes, but I've seen improved app launch times from 'defragging' my reiserfs '/' partition (tar the files, reformat, untar to same place). This leads me to believe that there is, in fact, a structured 'closest to the top' file placement scheme in reiserfs. in any case, having the swap as a file inside '/' as opposed to a partition far away on either side of it seems optimal in 2.6, given that you only have one drive to work with.

            Even with multiple drives, running swap and '/' on the fast one
    • To do that you need a real operating system. Linux will let you put one swap partition on each controller, set them to the same priority, and it will automatically spread the access between them, getting a RAID-like speedup in your swap access times.

      So will Windows (NT, 2k, XP).

      Also, remember to put swap partitions (if you are using files you are hopelessly fucked) on the end of the disk, so that they will be on the outer sectors where the transfer rate is fastest.

      Putting them in the middle of the disk

  • by sICE (92132) on Wednesday March 24, 2004 @03:00AM (#8653632) Homepage
    This [ibiblio.org] Linux Mini-HOWTO might be of interrested to some /.ers, it describes how to share your Linux swap partition with Windows.
  • Good Results (Score:3, Interesting)

    by harryk (17509) <harryk20022002&yahoo,com> on Wednesday March 24, 2004 @03:01AM (#8653636) Homepage
    I too am in a similar environment as yourself. I took it one step further, and also setup the temp variables to use the same drive.

    I've noticed significant performance increases since doing, not to mention that I've freed up some space on other, more important drives.

    Good luck!
  • by WarPresident (754535) on Wednesday March 24, 2004 @03:07AM (#8653653) Homepage Journal
    An old, surplus, dedicated swap drive on its own channel: $0.00

    A RAMdrive from system memory: Under $100 [cenatek.com]

    A solid state disk drive you shove into a PCI slot with a bunch of SDRAM on it: Priceless [cenatek.com]

    For everything else, there's, Hey! Why would I pay more than a grand for a PCI bandwidth capped solid state drive when I can fill my memory slots and use RAMDrive at DDR bandwidth?

  • no sense in that (Score:3, Insightful)

    by zatz (37585) on Wednesday March 24, 2004 @03:08AM (#8653656) Homepage
    First, if this is a workstation for one person, not an application server, then you are not likely to feel performance is acceptable when paging does happen, regardless of the device where swap resides. Just because your OS installer insists that you allocate swap space doesn't mean you should use it often.

    Second, transfer rates have increased about ten-fold since that drive was manufactured. (Access times haven't.) While it is ideal to have swap space on its own spindle and controller, it doesn't make much sense to optimize details like that but use such a slow disk.

    Just make a swap file on your system disk and forget about it. If the rest of the machine is new, it should have enough physical memory that swap is mostly irrelevant.
  • Absolutely!!!! (Score:3, Informative)

    by OC_Wanderer (729511) on Wednesday March 24, 2004 @03:10AM (#8653661)
    From Windows XP back to Windows 95, gurus have suggested a fixed size of 2 or 2.5 times the size of your RAM. I keep it at 3 times, because I have CRS disease and can't remember the exact size. Better safe than sorry, since I have the room.

    Swapping on a separate drive is faster than swapping on the same drive. I've tested that. I also put the "temp" directories on the separate drive, as well as the data directories for my applications. This includeds the mailbox for Outlook Express and the temporary internet files for Internet Explorer.

    There's a big bonus to setting up like this, besides performance. There's less to backup from C: drive!

    [Contrary to popular belief, not all nerds and geeks use OSS.]
    • Swapping on a separate drive is faster than swapping on the same drive. I've tested that. I also put the "temp" directories on the separate drive, as well as the data directories for my applications.

      For Solaris 8 and 9, at least, /tmp is swap (and RAM, using virtual memory for storage). This makes doing file operations in /tmp very very fast, but the user always has to take into account the amount of virtual memory on the system.
    • From Windows XP back to Windows 95, gurus have suggested a fixed size of 2 or 2.5 times the size of your RAM.

      That advice goes back to the days of Win 3.1, probably even further back, and it's bullshit. Any "guru" who makes such a blanked suggestion is talking out of his ass. He read it once ten years ago and is just parroting it.

      The point of having so much RAM is so that you don't need as much virtual memory. I have 512 MB in my current machine, it would be idiocy to use 1.25 GB of my HD for swap that I
  • I have two ide drives and 512M ram. I have the first 512M on each drive as a swap with linux stripping the swap. (See "man 2 swapon", "man swapon", "man 5 fstab" and set the priorities of each partion to be the same) I did this on the assupmtion that the bottleneck is likely to be disks's read/write speed, not the controller.

    Like you I'm also not sure if it makes much difference but my system certainly seems to often be swap limited. I currently have KDE3, several gnome apps, a browsers with 4 windows (20+

    • Controller limitations on IDE drive subsystems mean one read/write process at a time - thus putting half your swapfile on one drive and half on the other really don't gain you anything on an IDE system.

      If you had one drive on one controller, the other drive on a different controller (or if you were using SCSI) and you will see gains.

      That said, if your system seems swap limited watch the memory utilization - if your system has 512M and it is using all 512M of it, add more RAM for better performance (disc
  • by PurpleFloyd (149812) <zeno20NO@SPAMattbi.com> on Wednesday March 24, 2004 @03:14AM (#8653679) Homepage
    As far as using the HD goes, it sounds like a good idea, albiet with some conditions:
    • If you're planning on spending any money on this, it would be better off going towards more RAM.
    • If the drive isn't as fast as your primary HD, it may not be as good a deal as you might think. Remember that the non-DMA access modes used by older IDE drives, can eat up your CPU and thus any performance gain. Of course, this isn't an issue with SCSI if that's what you're using.
    • If you use an app that has its own scratchpad requirements, you might want to put that on the drive rather than your Windows swapfile. Photoshop comes to mind immediately as an example of where this would be a good thing; it might also be good for dumping processed video onto (although if you're doing major video work, you should have a fast, preferably RAID-0, scratchspace, along with more reliable storage).
    As far as a fixed-size swapfile, it should help some in Windows; when you defrag, it will help to keep your swapfile coherent as much as possible. Of course, if the swapfile is the only thing on the drive, it won't matter too much. If you do go for a fixed size file, make sure to make it larger than you ever think you'll need - it sucks to run out of memory when you're doing a lengthy, complex operation. One rule of thumb (not as valid these days) is to set your swap to 2x your physical memory. Another, which I use, is to simply take the most memory you'll ever think you'll use and then add a 50% safety factor. Remember to resize this if you ever start working with really large stuff - high-res video, 3000 x 3000 pixel Photoshop images, etc.

    Finally, remember that idealy, you never want to hit swap at all. If you're experiencing problems with thrashing, you should probably either pare down your system (do you really need to run that IM program all the time? all those systray utilities you never use?) or simply bite the bullet and get more RAM. Even the fastest hard drive can't touch RAM for speed, and seeing your system hit the pagefile for routine tasks means it's time to put a new stick of RAM into the beast.

    • " Remember to resize this if you ever start working with really large stuff - high-res video, 3000 x 3000 pixel Photoshop images, etc."

      good god I am fu@#ed... I'm about to start working on 3000 x 3000 res video..... any sugeestions on what kinda system i should buy to do the editing?
  • You don't specify how much RAM your system has, nor how much you actually use your swap space.

    If you really hit your swap hard, then I guess installing a dedicated swap drive would make sense. Of course, so would upgrading your RAM, which would have a much more positive impact on your system's performance, and without the additional heat, noise, and power consumption that adding another drive would.

    As another poster mentioned, the rule of thumb is to have twice as much swap as physical ram. Personally, I
  • Because not only will you get to play with antiquated technology, (yeah... 2GB is antiquated now.) but you get not one but two slashdot articles out of it!

    Just remember, you have all your time to avoid the slashdot effect, so you better have mirrors, boy. There ain't no excuse!
  • by skinfitz (564041)
    Does it make sense to install the 2GB drive on its own controller and use it for a dedicated, fixed swap file?

    Yes.
  • Just my 2c: I used to own a machine with limited RAM but with two HDDs. I split swap on dedicated partitions on both drives with the same priority (in Linux, I don't know if Windows can do this) and when I needed to swap, the performance increase was huge.
  • One Word Answer: No (Score:5, Informative)

    by silverfuck (743326) <dan,farmer&gmail,com> on Wednesday March 24, 2004 @05:28AM (#8654123) Homepage
    Okay, so this is too late for all but the most sad of slashdotters to read it, but here goes:

    If the drive is 2GB, then don't be so sure that it is fast - it may have been when it was bought, but that was 6 or so years ago at least. I would be very suprised indeed to see more than 4-5MB/s sustained read and 2-3 write; there have been a lot of advances in the last few years.

    My current setup (1GB physical RAM) has 2GB set aside for each of Win2k and Linux in seperate partitions right in the middle (this will speed up average access times as the heads will have the least far to travel on average from any random point over the platters) of the raid array (and hench middle of both disks, as it is RAID-0), which I know to be fast - benchmarking has pegged it at greater than 110MB/s sustained. Windows will hit the swapfile no matter what (just try setting the swap to 0, even on a well-heeled system, and watch it complain at bootup/logon), so it gets 512MB to play with just at bootup and can go all the way to the end of it's swap partition if it wants. Linux, well, that's another story (currently support for the raid array is patchy, so not running linux - the partitions are still there, though, waiting for filsystems!), but as everybody knows, linux is very aggressive about swapping stuff out and using physical RAM as a disk cache, so again I expect it to hit the swapfile after a few days (hours?) running, but be perfectly happy with 2GB.

  • If thrashing is causing degradation, I would seriously consider increasing RAM before improving on the swap drive.

    Check the performance specs for that 2gig drive first. If you are connecting an older, slower drive, you may actually worsen performance. For best performance, use a drive that can supports whatever performance features your mobo offers ( UDMA-66, Serial ATA, etc... )

    IF using Windows 2000/XP you can spread your page file accross multiple hard drives.
  • Yes, definitely (Score:2, Insightful)

    by BoogieChile (517082)
    I've always gone for the extra channels when I'm buying a motherboard. Windows and apps live on one drive, swap/temp files and data on the other.

    Real world experience - Rally Championship 2000 - swap file on the same drive as the game - loading times were long - 30 seconds or more. The indicator bar would move for a bit, stop for a bit, move for a bit, stop for a bit...

    Change the swap file to the other drive and the level loading time went away. 18 seconds.

    And the progress indicator keeps moving all the
    • Real world experience - Rally Championship 2000 - swap file on the same drive as the game...

      The last time I had a game use swap was Warcraft III on a 256-meg machine, and saw slowdowns like the one you mentioned. Rather than put swap on another drive, I stuck another DIMM in the machine, and the problem was solved. : )

      steve
  • ..is to put the swap on a drive other than the OS (not just a different partition), and on a different channel. I've also heard to put the swap start/stop at the same size (so its not fighting the filesystem for space) and to have the size be 2.5 to 3 times the amount of physical RAM installed.

    If you're running Windows NT/2000/XP, make the partition in question NTFS too.

    I'm running XP Pro with 512MB of PC2100 and have my swap start/stop at 2GB (ok, 4x my RAM) on an NTFS partition. The little trashing I do
    • If you're running Windows NT/2000/XP, make the partition in question NTFS too.

      Why? NTFS is slower than FAT, offsetting the gains you might have made by your other tweaks. If you're worried about someone being able to read what's on the partition easily, well, they still can if it's NTFS.

      How reliable is that 2GB drive though? I guess it doesn't really matter, cause if the drive fails, the OS should move the swapfile back to the default location.

      If the drive fails, you've just experienced roughly t
      • Why? NTFS is slower than FAT, offsetting the gains you might have made by your other tweaks. If you're worried about someone being able to read what's on the partition easily, well, they still can if it's NTFS.

        Slower how? In accessing files? This is just for the pagefile. And NTFS is better as far as fragmentation goes - less fragmentation with NTFS than FAT or FAT32.

  • I've got a pretty standard computer with reasonably fast drives.

    So you don't need to do anything. Leave it alone. You're not going to notice an ounce of difference. All you'll be getting is the extra noise and heat of another hard drive, which will be rarely, if ever, be getting accessed. No need to do it.
  • Apparently we're dealing with Windows, so I'll chime in ;-)

    Depends on your PC and what you do with it. Putting the swapfile on the outside edge of the fastest disk that does *not* have Windows on it is generally the best idea. If you're concerned about dissimilar PIO or UDMA transfer rates, if your IDE controller supports multiple media transfer rates (most IDE controllers built after about 1998 do) you don't have anything to worry about. There's no reason I can think of to have multiple pagefiles on a

  • separate drives, esp. on a separate channel or controller, will always help.
    but if you're dealing with xp, you can also gain some speed by NOT using ntfs on that drive. instead, use fat32- your swap file is not a file that needs full ntfs (permission or security or compression or encryption) complexity.
    combine that with a fixed size, from the word go, and you can get very nice speed bumps.
  • If you've got to swap, then yes, a separate drive to use for swapping is the way to go. It will prevent thrashing between your swap partition and your main partition when working with large executables or large blocks of data. You'd still be better off, however, by blowing some cash to get 2 gigs of RAM and disable swapping entirely.

Adding manpower to a late software project makes it later. -- F. Brooks, "The Mythical Man-Month"

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