A Hardware Interlude, With Pliers

When it came time to replace my always-on home Linux box, I settled on the Intel Atom in its dual-core flavor, and set about building a small system based on Intel’s D945GCLF2 motherboard. The idea of a system that draws 45 watts when running full out was compelling.

I also wanted quiet. Several reports noted that the fan that comes on the board is noisy. The guy at the local computer store who sold me the parts confirmed the problem, and handed me a Zalman ZM-NBF47 fanless northbridge cooler as a replacement.

When I put the system together, it looked like the Zalman wouldn’t fit. The CPU heatsink blocks one orientation, and RAM blocks the other. So I left the stock heatsink/fan in place. Big mistake. Lots of noise.

After a bit of head scratching and some Googling, I found the trick.

First, mount the clips on the Zalman and bring them out on a diagonal. Then, with needle-nosed pliers, bend the hooks backwards like this:

Zalman heatsink with hooks twisted backwards

Next, remove the stock northbridge heatsink and fan, clean off the old thermal grease, and lay down a new coat from the tube that comes with the Zalman. Set the Zalman down diagonally, and attach it through the back side of the hooks on the motherboard, like this:

Zalman heatsink hooked onto Motherboard

It’s a tight fit. There’s less than 1/8″ clearance between the Zalman and the RAM stick, and I bent a few of the fins up so that they wouldn’t touch the CPU heatsink. The Zalman is quite warm to touch, so you’ll want a case with good ventilation.

The result, with the board in a case with a fanless quiet power supply, is a very quiet system. If I listen, I can hear the disk spinning, but that’s it. Bliss.

I’m sure that replacing the stock heatsink/fan voided the warranty on the board, but if you insist on quiet, it’s worth the risk.

The D945GCLF2 with 2Gb seems to run Ubuntu 8.10 without any problems. The onboard video drives a 1600×1200 LCD reasonably well, though there’s no mistaking it for a gaming box. I haven’t tried audio yet. One pleasant surprise was checking /proc/cpuinfo and finding four processors listed instead of the two I expected. Each core is hyper-threaded.

Addenda: There’s a good discussion on quieting this board at silentpcreview.com. Note in particular concerns about how hot the chipset runs, and assumptions about the fan providing cooling for the passive heatsink next door. Taking a closer look at the power supply in my box, I found that it had a very quiet fan that provided airflow over the southbridge heatsink. If you don’t have airflow, the ZM-NBF47 might not be what you want.

A discussion on the Ubuntu forums has instructions for enabling lm-sensors so that you can see the chip temperatures.