Video Card with CPU Heatsink

In August of 2010, I bought an AMD Athlon II x3.  I was surprised how puny the heatsink was. It was sufficient, but it didn’t do a very good job. The CPU heated up to 65C with the fan roaring past 5000RPM and less than 75% usage. I did not find this acceptable, and replaced it with a new one.

In my Linux computer I use an Nvidia 7900GT, which for some reason doesn’t work in Windows anymore but works great in Linux. It never really reached dangerously high temperatures before but it has gone as high as 75C under load. The HSF that came with the video card was almost entirely copper, and so it weighed about the same as the AMD heatsink even though it was smaller.

I spent a few minutes trying to think about how I could mount the AMD heatsink on the GPU. Interestingly, the AMD heatsink was machined so simplistically that the fan screw holes go straight down to the bottom of it, and just happened to align perfectly with 2 opposite screw holes on the GPU:

Screws to mount CPU heatsink

I’m aware that two of the screws did not mount, but the HSF is pretty sturdy. It wiggles a tiny big if you force it to but it is aligned properly. Next I had to figure out how to get the fan spinning. The GPU had a tiny 2-pin fan connector, whereas the CPU fan used the standard 3 pin connector. I took out some pliers and attempted to pull off just the plastic surrounding the fan socket on the GPU, but annoyingly the pins came off with it. Not wanting to damage the perfectly good fan, I replaced it with another that had a faulty rotation sensor.  Then, I cut off the fan connector and soldered the wires onto the GPU board. The final product came out like this:

Surface of GPU with CPU heatsink

Then came testing the new mod:

HSF GPU Load Temperature Fan
AMD idle 40°C 30%
Stock idle 46°C 30%
AMD full 55°C Avg, 57°C Max 40%
Stock full 65°C Min 40%+
AMD full ~60°C *16%

 *(If the went below 16%, it would sometimes stop moving)

I found it interesting to see how much more heat the crappy AMD heatsink would dissipate, even though it had roughly the same mass with a worse material. In most situations, I would not consider anyone to do this because this mod takes up 3 whole expansion slots. Luckily for me, it doesn’t matter because I had no use for what it covered up.  Great for overclockers though!

Whole computer with CPU heatsink on GPU

Yes, I realize that the PCI-e power connector is not plugged in.

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