Quieter PCs

[Will be adding pictures later.]

Since my Quiet P4 document of several years ago, I've built two newer desktop computers, one as a backup (spare desktop) and one as a replacement for my main desktop. (Like my earlier PC writings, this one will become obsolete after I write it and seem quaintly anachronistic within a couple years. Technology marches very quickly.) The big story is improvements to the main desktop machine, but let's start with the backup which gave valuable experience with the Antec "Performance" line of quiet cases. The backup is actually the second most recent computer.

Backup Desktop: Pentium 4 2.4 in Antec P150

The backup recycled an old, but sturdy and reliable Intel D850EMV2 motherboard and Pentium 4 2.4 with 512MB of Rambus memory. I got a BFG GeForce 6600 GT OC AGP 128MB as basically the only AGP board I could find with two Dual DVI digital video outputs for use with newer dual LCD monitors. It also turns out that the Nvidia video drivers are very well supported under FreeBSD (and Linux and Windows). The machine is set up as dual boot FreeBSD and Windows. It usually runs FreeBSD.

CPU cooler is an Arctic Cooling Super Silent 4TC like I used on my original P4 1.8. It runs a bit hotter on the 2.4 than on the 1.8, but the fan turns slowly at low loads due to the temperature control (via a thermistor stuck into the heat sink fins) and speeds up for higher loads. It works well and is very quiet. (The 4TC is slightly better suited to slower CPUs like the 1.8, but worked fine in the 2.4. It was not really adequate for a P4 3.2 where it ran too hot and the fan turned too fast most of the time.)

Video cooler is actually a new, closeout Arctic Cooling AMD CPU cooler which I thermal epoxied (Arctic Alumina Adhesive thermal epoxy) to the main GPU chip. I also thermal epoxied some sheet aluminum to the video RAM chips, and epoxied those to the AMD cooler. The sheet aluminum went onto the RAM first, since it's lower on the board than the GPU chip. In other words, the sheet Aluminum was used as a shim to make the RAM chips the same height off the board as the GPU chip. The shims were allowed to fully cure first. Then the heatsink was epoxied to the GPU and RAM shims. The sheet aluminum and heatsinks were properly scruffed up with sandpaper then cleaned with ethanol before epoxying.

Needless to say, the shims and heat sink had to be carefully positioned to make everything fit the board and computer, since this was all a non-standard use of the cooler. The cooler had way more heat dissipation than was needed, and was somewhat too heavy for the video card. To help support the weight, I ran some zip ties from the unsupported corner of the card to the power supply bracket above. The other slight mistake is that I didn't press down hard enough on the epoxy when it was curing, so the epoxy may have been a little thicker than ideal. Remember that thermal compounds should be as thin as possible. The closer the heat sinks are to what they are cooling, the better. More, thicker thermal compound is bad since the compound itself doesn't conduct heat as well as the chips or the heat sinks. It should always be a thin as possible.

The real secret of the computer is the Antec P150 case which a friend told me about. This is a Mini-ATX case with much of the same design thinking as the Antec P180 and P182 quiet cases. It is an all-steel case with vibration damping on the side panels, one large, slow turning 120mm exhaust fan, and a front panel which blocks direct sound output from the front air vents while still allowing plenty of air in via the side air intakes formed at the left and right sides of the plastic front panel. In other words there are two front panels: a metal one that's part of the case and has the front-facing air intakes, and a plastic one that has side-facing air intakes. The plastic front door blocks much sound from coming directly out of the metal front panel. Another major noise reducer are the very soft Silicone hard disk mounts. They decouple much of the drive vibration from the case.

There are many other finely-engineered sound, thermal and airflow details that are too much to go into here, but this case is very, very well thought out, quiet, and easy to work with. It's even pretty sleek-looking in a contemporary, consumer-industrial sort of way. The P150 is an excellent design that's probably only exceeded by the P180/P182.

Unfortunately the original P150 has been discontinued and modified slightly as the renamed Antec Solo. Solo loses the hidden optical drive doors that P150 had, and thus loses one of the sound barriers. It may be a little noisier as a result. No idea why Antec had to mess with a good thing. I'd call it a mistake to do so.

Main Desktop Gets Series Of Upgrades, Liquid-Cooling

My main desktop was upgraded in several stages.
  1. Since the Arctic 4TC wasn't enough cooler for the P4 3.2 on a new ASUS P4T-E motherboard, the CPU got a Thermalright XP-120 cooler in November 2004. Video was upgraded to ATI Radeon 9800 Pro 128MB around August 2004. Unfortunately one of the heat pipes in the otherwise nice Thermalright design eventually failed around September 2005 and burned the motherboard CPU socket, making the motherboard useless. The CPU still worked in a new ASUS P4C800-E Deluxe motherboard. CPU cooler was again a XP-120 which Thermalright replaced under warranty since the original one had failed less than one year from new. They did not pay for the new motherboard. Ran everything air-cooled for a while, but my faith in the reliability of heat pipes and heat sinks which depend on heat pipes was burned like the board. Since that CPUs kept getting hotter, and most of the big, new air-cooled heat sinks designed to cope with them seem depend heavily on heat pipes:

  2. The next stage was to liquid-cool the P4 3.2 and ASUS P4C800-E Deluxe and Radeon 9800 with a Swiftech Apex Ultra Plus kit purchased from SVC. This kit had the Apogee GT CPU water block, MCW60 VGA water block, MCW30 northbridge waterblock, MCP655 water pump, MCR220 dual length radiator, etc. The Swiftech kit is excellent. The Apogee cooler uses a low resistance, computational-fluid-dynamics-optimized, machined-copper-pin array. The MCW60 was essentially one of Swiftech's older CPU coolers and it too worked very well on the video card. The 220 radaiator is twice as long as the typical radiator (at the time) meaning two large 120mm fans could be used at lower speed to have more cooling at lower noise. Since then, triple and quadruple length radiators have come out, but probably mainly to deal with the growing component heat. There are also passive radiators with no fans that look and function somewhat like small room heaters. Also changed to a Western Digital 120 GB SATA drive.

    I built my own acrylic external radiator box that mounted 4 Arctic Cooling Fan 12 120mm fans in push pull (two fans pushing, two fans pulling), and used a Cooler Master Aerogate 3 fan controller to run them at 600 RPM for regular desktop use, and optionally cranked them up to about 1000 RPM for gaming. The radiator box has half-round radiusing on the input to enable a smooth, hemispherical airflow, just like NASA's big wind tunnels.

    The radius lowers the input impedance, meaning air can be more efficiently pulled in. Indeed air can be felt being pulled in smoothly from the front around to the sides of the intake radius, exactly as hoped for. Conveniently, TAP Plastics sells half-round acrylic rods (think "D" shape or half of a circle) which I miter-framed and bonded to the front edge of the box. (Acrylic cement melts the plastic, so it's basically like chemical welding. The end result is actually a new, solid piece of plastic, not pieces of plastic glued together.) The external radiator box has Sorbothane feet for vibration absorption and sits on top of the case. The Arctic Fan 12s have open frames and an internal soft suspension that isolates the motor and fan from the frame. They're basically silent at low speeds, and no other fans have their excellent, patented design.

    Temperatures for regular computing (basically idle) were in the 30 to 40 Celsius range. Very cool and very quiet. Pump is fairly quiet at middle speed setting of 3. Quieter (almost silent) at slowest "1" and slightly noisier at highest "5".

  3. After dropping a screw on the nicely working, but aging and no longer competitively fast P4 3.2/ASUS, replaced the motherboard, CPU, memory and video card, power supply and disk drive. Pretty much had to replace them all since the old memory, AGP video, power supply, etc., would not work with any current replacement parts. Stuff changes too fast for parts that are a few years old to be usable with anything readily available in stores. It's annoying but inevitable thanks to Moore's law. But it also means getting a much faster computer each time.

    After research ended up getting EVGA 680i motherboard, Intel E6600 Core 2 Duo 2.4 (Conroe family), EVGA 8800 GTS video with 640 MB RAM, 2GB of OCZ PC8500 with custom heatsinks, Seasonic S12 650 power supply. Had to get a new water block for the new video card and got the Koolance VID-280. The Danger Den 8800 GTS waterblock may be a bit better, but the Koolance is good. Both cool all the major heat sources on the video card: the main GPU chip, RAM, voltage regulators, etc. Used a new Danger Den 680i northbridge cooler and moved the Swiftech MCW30 to the southbridge. (Nvidia doesn't use the two chips the same way as Intel uses their northbridge and southbridge and doesn't call them the same names, but I tend to think of them as being roughly equivalent. In both cases, the chip near the CPU essentially controls the flow of data over busses between memory, CPU and peripherals, and the other chip nearer the peripherals is more like an application and peripheral controller.) Be sure to get factory hard mount kits for all your chipset waterblocks. They're convenient and much less likely to risk damage to the motherboard.

    Note that the motherboard and video card are essentially made under contract for Nvidia in Taiwan and resold to EVGA and others. So, some companies selling Nvidia-based hardware may actually be reselling Nvidia-contract-manufactured boards. There's nothing wrong with that, and it probably makes quality control, support, design costs, etc., better, but it's probably with pointing out. EVGA has been excellent to work with.

    Changed drives to Seagate Barracuda 7200 RPM 300GBs in RAID 1 for quietness and reliability. The motherboard supports SATA at 3Gb/s, and the drives support native and tag queuing. The Barracuda 7200s are considered to be relatively quiet and reliable. They do seem quieter than my old Western Digitals. The MCW60 is currently unused. Sound is still handled by a Creative Labs Sound Blaster Audigy2 ZS at 96kHz/24-bit via S/PDIF over Toslink digital output to my audio system.

    Power supply was rated as quietest available at the time on Mike Chin's Silent PC Review, which is a font of information about quiet computers and was a major impetus behind the design and success of the quiet Antec Performance cases. Got the S12 650 thinking I might go SLI at some point, but even a single 8800 GTS is massive overkill for the old games I play. It does the Counter-Strike Source test at 250 frames per second without the second SLI board, for example. It renders Battlefield 2 at the highest resolutions and highest quality settings faster than my 1600 x 1200 ViewSonic PS790 main monitor can display. So a lower wattage power supply probably would have been ok, and slightly more efficient too. (The S12 650 is rated at 80%+ efficiency, but is oversized in my application. Switching Power supplies are usually slightly less efficient when under-loaded.)

  4. Most recently have moved the components into an Antec P180 v1.1 case, which is basically the same as the P182, in that it has the same cable management, water tube grommets, interior sheet steel on side and front panels, etc. P180/P182 is a very interesting case design which puts the power supply and hard drives in their own lower tunnel. This is smart because it means the main heat-generating components, which are on the motherboard, won't heat up the air the power supply uses to cool itself. It also means the main part of the computer only sees the heat of its own components and not the power supply. (This is less relevant in a liquid-cooled system, since the liquid effectively takes the heat out of the case, i.e., without significantly heating up the air inside the case.) The design also means that the hard drives are cooled by the power supply fan drawing air from the front of the tunnel, over the hard drives, before cooling the power supply. Very clever.

    Like the P150 (and probably other Antec cases) the P180 uses the front door as a baffle, blocking most of the direct sound while having a huge air intake area at the sides of the door. The large area means lower air velocity for the same airflow volume. Lower velocity usually means lower noise, which is the same reason two large, slow-turning exhaust fans are used at the rear and top of the case.

    Regarding the side and front panels, the original P180 had a single sheet of steel on the outside of a plastic core. The current P180 and P182 have a steel, plastic and steel sandwich for the side and front panels, which forms constrained-layer-damping, as I used Dynamat Super on my old Cooler Master case. With contrained-layer-damping, a higher-density material is used on the outsides and a lower-density material is used on the inside. Essentially this traps impinging vibrations into the middle layer and dissipates it, reducing the noise and vibration transmitted to the outside of the case. Said another way, the soft center layer of the sandwich acts like a one-way trap for sound caught between the harder metal panels on the outside. The relatively soft plastic dampens the sound as it bounces back and fourth between the metal. Sound gets trapped between the metal panels and can't get out.

    With its dual chambers, the P180/2 is a a few centimeters taller than a regular case. The P180/P182 also has Silicone hard drive mounts, which seem to greatly reduce transmission of hard drive noise to the case, but it has two hard drive cages mounting three drives in the upper cage and four in the lower cage. Putting hard drives in the lower cage is recommended by Antec for quietest operation. It has four 5.25 inch optical drive bays and top and one 3.5 in bay below them.

    Other modifications along with the move:

    The mCubed also controls the four radiator box Arctic 12 fans. Given that it has 20 Watts of capacity per channel, 7 Watts worth of fans should cause it no trouble. (Those 4 fans will probably be running at less than 3 Watts total most of the time.)

The Memory Cooling Problem

While it may be possible to cool typical desktop memory just by dumping the heat to the surrounding air in a disorganized, ad hoc way, memory heat dissipation seems to be a major weakness of the escalating clock rates of higher-performance memory. Memory busses capable of 1066 or 1333 MegaHertz are becoming commonplace, but memory that can actually operate at those rates is comparitively rare, expensive and unusual. The high heat is largely due to the voltages that need to be run higher to keep the memory stable at elevated speeds, and both the higher frequencies and higher voltages result in much greater heat. (Since the normal operating voltages are now so low, like 1.8 Volts, increasing that to say 2.4 volts means roughly one third more heat due to the higher voltage alone.)

I got some higher-speed OCZ PC8500 memory, with a 1066 clock to match the motherboard's 1066 FSB. In principle the best performance happens when the memory and FSB clocks match. I actually had one stick of the OCZ memory fail, probably due to overheating, and without overclocking it. OCZ kindly replaced it under warranty. Most likely the meager heatsinking failed. The stock heatsinking consisted of a couple pieces of perforated sheet aluminum stuck to each other with thermal tape, with thermal tape attaching it to the memory chips. So I looked into ways to cool the memory better.

OCZ and possibly others do sell factory memory modules with liquid cooling ports. There are aftermarket water cooling systems also, usually with 1/4 inch (6mm) hose support. I didn't like the small tubing sizes and the additional adapters and backpressure entailed. I considered making some home-made water cooling with larger tubing, but the memory sockets really aren't meant to support much force. (The big tubing is stiff and puts a strong spring force on anything attached to it.)

Some of the fastest memory is sold with something more like real heat sinks. They appear to be using crosscut Aluminum extrusions of a couple millimeters thickness extending well above the modules, but even those look fairly minimal. Corsair and others also sell fans to blow air over those heatsinks, which probably does improve their heat dissipation somewhat. I listened to the OCZ memory cooling fan at Petra's and it was very quiet. It may be a viable solution for me if it will fit over my modified modules.

I decided that air cooling was probably the most compatible with the sockets and found the largest Aluminum heat sinks that would still allow air to pass between the single pair of dual channel OCZ memory I was using. With a single pair, the modules use alternate sockets on the Nvidia motherboard, so that helped in space available. It also means I won't be able to fully populate 4 sticks since my current modules block the empty memory slots. I don't expect to need more than 2GB of RAM any time soon. I basically use my main desktop for simple applications and games. My heavy computing is done on FreeBSD servers in datacenters. I also hope and expect to never use Windows Vista.

The BGA heatsinks are 28 x 28 x 9 mm and are meant to cool old/low-end processors or support chips. They were bought online as surplus. I haven't found a Thermalloy part number for them, but they are some large heatsink manufacturer's standard part. The original OCZ heatsinks, as on most RAM, are thin sheet metal.

The original heatsinks and thermal tape were carefully removed with a lot of mechanical tinkering, Goof Off and ethanol solvents. The Arctic Alumina ceramic thermal epoxy was used as sparingly as possible; about a third of a grain of cooked rice or less per chip. Even then, some epoxy oozed out under full pressure, which is a good thing. Thermal compounds should be as thin as possible, and if some is oozing out, then that means the amount between the chip and heatsink should be minimal. Use as little as possible and press hard when it's curing.

As if to prove a point, I stupidly left the fan off the RAM while playing some games, thinking the big heat sinks may afford enough cooling without it, but the PC8500 RAM seems to have burned up. Apparently the BGA heat sinks do need more airflow than the ambient airflow inside the case to cool things properly. Video started to have frozen frames, black backgrounds, etc., and eventually the system would not boot, giving a BIOS memory error "C1". Replacing the memory with Crucial Ballistix PC6400 low latency (4-4-4-12) on sale at Frys for $30 after rebate, the system works perfectly again. I'm using all automatic/optimal settings, which are actually 5-5-5-15. Supposedly this RAM overclocks well, but I don't want to risk the system crashing again, so I probably won't overclock anything at all. Trying to decide how to cool the new RAM. Currently it has stock sheet metal heat sinks and a 120mm fan blowing down on it. May use BGA heat sinks and a shrouded fan, per the original plan but need to design and construct the shroud. These Crucial modules are 8 chip (single-sided) versus the 16 chip (double-sided) OCZ, which is nice since it means only one side of each module needs to be cooled. So half as much heat-sinking is needed.

With the BGAs, the memory temperature is well below 40 Celsius under gaming load. With the stock sheet metal heat sinks, the temperatures go above 40 Celsius. Both are measured with a temperature probe on the heat sinks right next to the chips, and with the 120mm Scythe fan blowing in free air several inches away at medium speeds. That's with the fan hanging in free air with no air shroud on the memory.

Speaking of servers, server boards handle memory cooling better than desktop boards. For that matter the thermal design of server boards is far superior to most desktop boards. Servers use straight-finned CPU heat sinks, memory modules and hard drives all lined up from front to back with airflow running directly over them from front to back. Servers also usually have fan shrouds that direct air over the CPU and memory. Most desktop boards have the memory modules aligned vertically, basically against the direction of the main front-to-back airflow. This design may be adequate for relatively cool memory of yesterday, but seems inadequate and inappropriate for faster, hotter memory of today. On the other hand servers are meant to operate with much less concern for noise, and have fans that constantly run at high rpms. The latter would be unliveable in a home or office machine. But the fan shroud design from servers could work in a desktop if the airflow direction was changed.

Inintially I made a memory fan shroud out of a small water bottle. It was quite effective with a thermally-sensitive fan controller, but the small fan was very noisy. (The fan came from the 680i motherboard Northbridge cooler. It's a tiny ADDA AD0512HB-G76.) Ideally the shroud should expand to a much larger size to accomodate a large, slow turning fan. That's what I'm working on now. The server shrouds are all very close to their components, so I'm thinking of an acrylic shroud with fans at right angles to the memory, but offset above the modules.