Underclocking for a Quiet Machine? 62
The Fun Guy writes "I'm running a PIII 600MHz, which I'm thinking of upgrading. If I could get rid of the fan and run more quietly, I'd love to. I run office-type apps, so I don't need the fastest processor around, but I also run d.net, so I'm constantly pegged at 100% usage. Aside from the obvious fact that your CPU is running slower than the listed speed, is there any downside to buying, say, a 1.8GHz chip and running it at 900MHz without the fan? Any experience or FAQ's to share on this?" We've covered this topic several
times
before, with some good feedback, however most of the approaches don't discuss the use of underclocking to accomplish this, although one common suggestion from the comments is to use a non-Intel processor, if you can. Have any of you tried underclocking your CPU to allow it to run silently? How far do you need to underclock a processor in order to enable it to run without a fan?
Water cooling, honey (Score:2, Interesting)
Since I run an Athlon XP machine with lots of hot hard-ware in it, I found that underclocking to take a few degrees off of the CPU temperature was futile. It made about 10 degrees F of difference with the fan still on, and that just didn't seem like enough to risk my investment by running it without any active cooling.
So, I went with a water cooling solution. Although I decided to roll my own system using components available over the Internet, there are several cases [hardocp.com] that come with water cooling built in. Some of them don't even require a water pump, which is a super big plus if need absolutely zero noise, like me. I've been quite satisfied with mine so far, however, your milage may vary.
easier way... (Score:5, Interesting)
- cpu fan
- disk drive
- case fan
- video card fan
- power supply fan
- cd spinning
Ok, so my way of solving the problem doesn't involve underclocking, but it works better:I put the computer in another room.
Get a good monitor cable (one with ferrite cores) and a keyboard extension cable and run them through a wall to the computer in another room. Now *that* is quiet. And it costs maybe $50.
Now to be honest, that's not exactly my setup. I actually have a KVM switch and hook to several computers in the next room. I have a nice quiet bedroom with a keyboard, monitor, speakers and a usb KVM switch. If you look at http://www.belkin.com you'll find kvm switches that switch audio too.
My theory (Score:3, Interesting)
I haven't actually tried it, and I'm sure some joker who doesn't know what he is talking about will chime in here and pose as an engeneer and say it can't be done, but I really thing this will work.
You won't be able to lower the voltage much, because you'll need to meet a certain minimal signal level. OTOH, less clock means less noise, and every little bit helps.
Also consider using a notebook HDD. Quieter and cooler.
Good luck!
-Peter
There are always sound-deadening cabinets... (Score:4, Interesting)
I've seen a huge amount of discussion over the past few years about doing things to computer cases to deaden sound. Now, one person in this discussion started thinking outside the box, talking about his putting the computer into the next room and running cables through the wall -- effective to some extent, but absolute hell when you have to put a CD-ROM into the drive, don'tcha think...
What I've been looking to do is build a proper sound-controlled cabinet for my computers. It would be an enclosed cabinet with doors, fans (ducted at inflow and outflow ports with sound-proofing material) to ensure enough air flow to keep internal temps down, built-in power distribution, built-in Ethernet (I have a 24-port 100-base T hub), and sound-sealed cable ports for the KVM switch and external connections.
Some design points:
The cabinet needs to be deep enough so that the system units will have adequate front and rear clearance for airflow. Experiments with standard cases tells me that you need at least four inches rear clearance and six inches front clearance. The extra clearance in the front is dictated by CD-ROM and DVD-ROM drives, so that the door of your cabinet doesn't interfere with the CD/DVD-ROM tray. Given that the deepest cases are about 20 inches, that means you need an inside depth of 20 + 4 + 6 = 30 inches. Plan on 36 inches of depth for the outside dimension
Your primary sound barrier will be dense material, such as plywood. If you can get birch plywood, this will give you better sound control because of the increased density of the wood. It's tempting to go very thick, but 5/8 inch should be plenty good. Consider using 1x6 for the framing, and be sure the plywood is braced at least every 18 inches with framing.
Most acoustic treatments will require about two inches of depth in order to be effective across the "band of annoyance" (200 Hz to 4 kHz). Thick-pile carpeting (make sure it's flame-retardant!) can be surprisingly effective, and cheap when purchased as end-rolls or remenants. Fiberglass batting and rock wool are also effective, although the stuff is tricky to work with safely. For the sides and the rear wall, standard acoustic tile or ceiling panels can be effective. For ducts, the goal is traverse absorption, so materials like acoustic tile may not be appropriate as they tend to best absorb sound hitting the tiles perpendicular to the surface.
Design the airflow so that air deflects around sound baffles; this prevents direct ray-path propagation of unwanted noise. For example, an air intake can be done by using a front floor-level opening, a baffle panel of burlap-covered 1/4-inch plywood, and a 5/8-inch plywood shelf for the computers that stops six inches from the front of your cabinet. This design directs the airflow to the front of the computers, which from most cases seems to be the most desirable. A similar baffle system at the top of the cabinet can serve to exhaust air, again using baffle panels to break up any direct ray paths.
Any air-motion equipment should be suitably baffled as well. Large low-RPM fans work better than small high-RPM fans.
Finally, cable ports need to be sealed acoustically. Consider rubber gasket material, or the "tube foam" you can find at some fabric shops.
For my prototype, I'm using a rack cabinet I got at an auction last year. The metal skins (including the top one) is replaced by 5/8-inch plywood, faced on the inside with long-nap carpeting. The air intake at the bottom of the cabinet uses exactly the baffling technique I described above, using burlap soaked in fire retardant. Air exhaust is still a problem. Cables go through two slots in the back of the cabinet. The "door" is currently a removable panel of carpet-faced plywood, but I have designed a quad-door arrangement - this lets me get access to the CD-ROM drives without opening the entire front, yet provides for service access easily.
Temperature monitoring is a bit of a problem right now, a problem I hope to solved via eBay.
When I have more, I'll put it on my Web site and let you all know about it.
(One thing: I'm a bachelor, so I don't have a wife to worry about. Your mileage may indeed vary.)
Personal Experience (Score:3, Interesting)
Since performance was not an issue (about 10 clients).
I decided to underclock the processor (a very old CyrixPR166). The right clock speed would have been 133, but I clocked it to 100.
This was a zero maintenance server, in fact it ran for about two years without a single problem.
After two years, it needed an HD upgrade, and I opened it, to insert a new HD. To my surprise, the CPU fan broken, and in fact, from the dust I guess it didn't work for some months, but still the CPU had no temperature problems.
What's the moral of this story? Don't use the muscles (Mhz) if you don't need to!