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Rusty's Quiet In-Desk PC

October 15, 2002 by Russ Kinder

Computing enthusiast Russ took a wholly different approach to the issue of PC noise: he built his right into the desk! While it may not make the industry scramble to define a new desk (not desktop) form factor, Russ's inventive techniques will surely have quiet computing enthusiasts poring over his fine work. The article here is a preliminary work, mostly a visual exposition; the author hopes to fill out the details in time.

- Editor's Note by Mike Chin

This began as a simple project to quiet my screamingly loud PC. The end result was a completely different beast than I started out with. It was a lot more work, but I'm quite happy with the results.

This article is a temporary measure. I'm in the process of writing an in-depth review of the construction of my system, but given my complete lack of free time lately this is going to serve as a stop-gap measure. (I'm currently working on my Master's of Architecture Thesis, while working full time)

So for now I'll just post some pics for feedback. Any comments, questions, or ideas are much appreciated.

The problems I had with my original computer were twofold. It was way too noisy, and it took up valuable desk space. I tried moving it to the floor under the desk, but that didn't help the noise any, and it seemed to trap much more heat when it was down there. So I came up with the idea of moving it onto the printer shelf of my desk. This was a useless little sliding shelf, only 14" wide, nowhere near wide enough for the printer that I have. But the space is also only 14" tall, too short for almost any ATX case. After searching in vain for a case that would fit, I decided I would just build my own.

Here's the result.

This is what it looks like outside the desk. The front and back are 1/2" MDF, and the bottom is the 3/4" particle board of the original shelf. One immediate benefit of this case is the natural noise dampening of the wood.

Here's a profile shot showing how the internals relate to each other.

And below, one of the back . The back plate, motherboard tray, drive rack, and power switch were all cannibalized from an old case.

The drives up front are a Pioneer DVD-rom and a Teac 40x CD burner. The hard drive is a Maxtor D740x 40Gig, with liquid bearings, that I've sandwiched, sidesinked and suspended. Hanging the HDD below the drive cage is a fairly new mod. It puts it right in the airflow path and reduced my hard drive temps by about 8C.

The graphics cards are pair of geforce2's. The AGP one on the right is a Ti. Its been modded with an old Celeron heatsink. The fan above it is an 80mm Papst at 7 volts, blowing upwards so as to not fight against the natural convection. The PCI graphics card on the far left is a Geforce2 MX, stock with its passive heatsink. Both cards are running overclocked. In the pic below, you can also see the modded Enermax PSU. I removed both the stock fans and replaced the 92mm that faces down with a Papst, also running at 7 volts. I closed off the other vent holes to prevent warm air being recirculated back into the case. Since this picture was taken I've replaced the ghetto-tastic masking tape with a sheet of aluminum mounted inside the PSU housing to block the vents.

The most important part of this silencing project has been the CPU cooling. The processor is an XP1900+, undervolted to 1.6 volts. The heatsink is a Zalman 6000Cu. The big fan is a 120mm Panaflo. It's thermally controlled, with the thermistor being epoxied to the top of the heatsink. When the machine is in standby, the fan runs at about 4 volts, and cranks up about 7V under full load. The key to making this work is the duct, shown below from left and right. I made it from acrylic. It forces the air to move parallel the surface of the fins, increasing the efficiency of the heatsink. The 120mm and the 92mm in the power supply are the only fans exhausting air from the case.

The temperature specs at 24° C ambient:

Hard Drive
42° C
33° C
38° C
100% Load
60° C
35° C
43° C

For the record, the complete system components:

AMD XP1900+ Undervolted to 1.6 volts, stock FSB and multiplier
Zalman 6000Cu heatsink Ducted to a 120mm thermally controlled Panaflo L1A fan.
Abit KR7A-133 motherboard Modified with passive northbridge cooling (Zalman ZMNB32J
512 megs RAM Mushkin latency 2
Geforce2Ti Modified with larger passive heatsink. Additional cooling by 80mm Papst fan @7 volts mounted on Zalman FB123 fan bracket.Overclocked to 275mhz Core/450mhz Memory
Geforce2MX400 PCI Stock passive heatsink; Overclocked to 200mhz Core/215mhz Memory.
SoundBlaster Live 5.1 Sound card.
3com 3CR990 NIC
Maxtor 40G D740X liquid bearing hard drive Sandwiched and sidesinked with aluminum plate, mounted in suspension.
16X Pioneer DVD-106S DVD-rom drive
TEAC CD-W540E 40X CDRW drive
Enermax EG365P-VE (FCA) 350W PSU Modified by removing both stock fans (80mm and 92mm) Replaced 92mm with 92mm Papst fan at 7 volts. Sealed supplemental vents to improve air flow.
Sony SDM-N50 LCD Dual monitors
Logitech Z540 4.1 surround speakers
No floppy drive (welcome to the 21st century)
Logitech dual optical mouseman
The cheapest keyboard I could find without all those useless extra buttons


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