Dual vs. Single Processors 27
Xanthippe asks: "I'm currently looking to build a new system and hunting for a within-reasonable-budget ideal. A friend suggested going with dual-P500 processors instead of an Athlon650. I wouldn't mind going with either, but I'd like to know how they compare. I know zilch about processors and their mysterious voodoo-god-like inner workings, but I can read a benchmark as well as the next geek-wannabe. Has anyone tried pitting a dual system against one of the 600+ AMDs? Are there any major advantages/disavatages in going with a dual system?"
Obvious difference ;) (Score:1)
It Depends (Score:2)
My personal choice: I got a board capable of dual Intel processors, but only put one Celeron 333 in it. I figure if I get really antsy for CPU speed, which hasn't been a problem yet, I'll either get a much faster single chip or buy a pair of moderately faster matched chips. The board was $235 about a year ago and was one of the cheapest dual-capable boards that supported 1 GB RAM.
Good luck with whatever you decide, and don't forget to make a web page describing your achievements!
Re:Obvious difference ;) (Score:2)
I checked shopper.com [shopper.com], and both a single unboxed Athlon 650 and a single unboxed PIII-500 are within $50-$75 of each other. Dual Athlons would be ideal (if the motherboards actually existed), but in this case you probably need to examine first how much you're willing to spend, and second, what you'll be doing with the box. Sometimes, I/O subsystems such as SCSI can make an equal or even greater perceived difference in speed.
If money is no object, get two of the fastest chips you can find. If you don't normally fork huge numbers of apache, g++, and gcc processes, the single Athlon may be a better value.
43rd Law of Computing: Anything that can go wr
It depends on the apps (Score:3)
Individual processes, however, can only make use of multiple CPUs if they are specifically written to do so (e.g., by using a threads library). Otherwise, they will simply run at the same speed as they would do on a single CPU. This gives rise to some interesting situations. At my last company, we were doing some fairly hefty image manipulation. The main conversion program ran quicker on the departmental laptop than it did on a 64 CPU Sun Starfire. This is because the program could only make use of 1 CPU, and the Starfire's ran at 200MHz, compared to the laptop's 250MHz. However, as soon as you try running lots of those processes concurrently, the SMP machine comes into its own.
So, in answer to your question, if you're running computationally intensive single-threaded applications, and absolute performance is a high priority, then a faster single processor will be better. Otherwise, you're probably better off with two slightly slower CPUs.
Get a dual mother board... (Score:1)
Anyway, I highly reccomend getting a mother board that can do 2 processors and if you need save the money by getting only one processor now.
The Net Express [tdl.com] site is a great site for doing research when building a system.
hope it helps
Citrix
It's more than just 2 CPU's vs 1. (Score:2)
Additionaly, if you use things like VR then you'll have a CPU for doing the VR work while the other one actually runs the application. If you're running a server the second CPU will be a big benefit.
All that being said, the big thing to realize is that there's typically a world of difference between SMP systems an non-SMP systems that goes well beyond the CPU. SMP motherboards typically have much fancier memory and I/O subsystems because they've typically been targetted at the server market, and also because if you have 2 CPU's it's just that much easier for memory and I/O to be the bottlnecks. SMP systems have to spend extra effort to allow cache coherency between the CPU's, and that usually means fancier memory subsystems. Of course, you'll also pay more for the motherboard.
My advice is this: if you're thinking of getting SCSI, go with SMP, as the benefits of SCSI and the benefits of SMP tend to align pretty well together. If you're going to play games, go for the single processor, as few of them take advantage of SMP at this point. If you're going to buy a lot of RAM, that's probably another good indicator that SMP is going to be helpful for you, as most (but not all - a lot of vector processing doesn't scale too well for SMP
Re:Get a dual mother board... (Score:1)
And I agree, get SCSI on the MB right away. You generally have to put a bit more money in to get a dual board anyways, any then the step up to one with SCSI on it isn't too bad. (A good SCSI2 card with bootrom cost more than my dual MB after all.)
I'm thinking of upgrading to 2 new processors currently, two celerons most likely.
Apparently the architecture for the AMD/Digital slot-A is much better with SMP (and more) since each processor have their own bus to the chipset, so they will most likely have better SMP perfromance. God knows when any will be released though.
Dual Processors good. (Score:2)
We had NT crash on us a while back (yeah yeah.. I know..) so we decided it would be good to run windows98 because of better hardware support for the VoodooBanshee we planned on puttin in there, as well as being able to run multiple monitors.
The speed decrease upon running a Non-SMP enabled OS wasn't significant. Well, that is, we didn't notice until we tried to burn a CD. The guy who usually uses this machine as a workstation was accustomed to working and burning at the same time. This is a joke with one processor on that machine.
I guess while in SMP mode, the machine monopolises one of the CPUs to handle I/O to the burner, and the other is put into the foreground.
Just my 2 cents, though.
Dual processors or not? (Score:2)
My situation might be similar to yours: A home user, dialup internet connection, a hobbyist programmer. For all of these things, fast processing is not the bottleneck - it is the disk drive.
However, I can beat just about anybody compiling a custom kernel!
Anyway, my point is, unless you know that you *need* an SMP capable system, you don't. An Athlon 550 will suit you just fine. OTOH, if you like ripping MP3s concurrently with a kernel compile, plus a session of Xchat, playing some MP3s and compiling the latest homework assignment - you will find that the dual processor system really rips. I know I cannot justify the expense of building the system, but it really rips *much* faster when you do many processor intensive things at the same time.
http://stuarthall.net
Do You Need 500 mHz Let Alone Dual 500mHz? (Score:3)
Probably not. I'd be willing to bet that most of the time (SETI, Dnet, etc. aside), you're current PC is sitting there spinning its wheels.
Except for a relative few, computers have far more CPU cycles than they need. Even my NT servers sitting on 450mHz processors are idle more often than not.
So, unless you have a clearly defined reason and performance statistics showing you that you need dual processors, you probably don't. Even if you do have performance statistics saying that you need more power, think twice about going dual.
Is your bottleneck the CPU? Can your application really use more than one processor?
For a single-user system, chances are one CPU is more than enough.
And, though I know this has been covered before, never buy a dual CPU board unless you are ready to put both CPUs on it when purchased. I've never met anyone who has actually put a second CPU in the box later. By the time you have the money or need to add a second processor, you can get a single processor that out-performs the dual along with a motherboard with all sorts of new bells and whistles for about what the the old processor cost you new.
InitZero
Re:Dual Processors good. (Score:2)
I'm planning an SMP system, but after those other purchases (and a new house), I'm way out of $$$......
Re:Get a dual mother board... (Score:2)
I'm still waiting for the dual-Athlon board, but I'm not holding my breath, either 8^)
What apps are you using? (Score:1)
If your doing 3D graphics (SoftImage etc), SQL programming/testing, large C compiles, or were addicted to Quake3, then a Dual processor motherboard makes sense (Dual celerons, slightly overclocked, is my recommendation). Otherwise, invest in a kick ass single processor Athalon system.
Now, if we were talking about a 6way ALR Pentium Pro system, then I would highly recommend it. Why? Pure geek value baby!
Jailbrekr
Visual Metrics? (Score:1)
Dual Boot - Dual Chip (Score:1)
Re:Obvious difference ;) (Score:1)
I have been wondering about this for a while too, so to test it out I compiled the newest Linux kernel I could find (2.3.48) with it's default options on the two boxes I have to hand: A dual PII-450 with SCSI (/proc/pci says it's an `Adaptec AIC-7895U') and an Athlon 750 with on-board EIDE.
Well.. the dual PII (using make bzImage modules -j2) managed it in 4 mins 3 seconds, while the single Athlon made 4 mins 15 seconds. So the single CPU option isn't too shappy, especially when you consider the far better floating point performance which 3D-Now allows (4 flops/cycle compared to the PII at 1 flop/cycle).
I'm sure these results would be different with PIII's, but then so would the price, and PII performance is probably closer to Celeron than PII.
It's a shame that there's no SMP Athlon boards yet (are there?)
Earlier SMP Discussions (Score:2)
Ask Slashdot: Is SMP Worth It? [slashdot.org]
Ask Slashdot: What's a Good Motherboard for SMP Linux? [slashdot.org]
Ask Slashdot: Building an Upgradable Dual Processor System [slashdot.org]
Would SMP help VMWare? (Score:2)
Thanks,
Jeremy
Re:Would SMP help VMWare? (Score:1)
I have a dual Celeron 400 running VMware... it runs pretty nicely... and I have even had a couple of VMware's running Win95 and had the base machine crunching SETI@home at the same time... however one of the main limitations of VMware at the moment is the video... DirectX support is limited so I doubt games will run well no matter how much processing you give it... also make sure you pick the right video card for your X server.
One of the REALLY nice features of VMware 2 (beta) is the suspend to disk... which means I can now run a virtual Win95 and when I don't need windows suspend to disk, shut down VMware (reclaiming the memory/resources for Linux) and when I need it again it is just a quick reload of the memory image and we are back running where we left off...
Re:Dual Boot - Dual Chip (Score:1)
Interesting, but this quite definitely isn't true. If the program isn't written using threads, NT will only schedule it for one processor at a time. Threaded programs, however, can use multiple processors concurrently.
I think we're talking at cross-purposes here, though.
The Bottleneck will be.... (Score:1)
"Why's that, Pixel?" I hear you ask? Well, if you don't go SCSI, odds are you're going to be I/O bound. The UDMA66 on this motherboard has been nothing but headaches, and besides, IDE takes CPU cycles (right?)
Anyways, if you're going to spend the money, get the most out of those CPUs. Get a SCSI card.
Re:Dual Processors good. (Score:1)
Get Matrox cards. G400 Dualhead and viola.
Heck, get two Milleniums. Whatever.
-sid
Re:Dual Boot - Dual Chip (Score:1)
Re:Do You Need 500 mHz Let Alone Dual 500mHz? (Score:1)
Re:Would SMP help VMWare? (Score:1)
Just a little side note, but Linux itself can sleep to disk. Check out one of the patches linked to on Kernel Notes [kernelnotes.org].