Geforce GTX 295 Heat Pipe



The Geforce GTX 295 is a monster of a video card. It is huge and relatively heavy thanks to the massive heatsink that transfers heat from the two, conjoined video cards. Yes, two video cards in one. I think Nvidia was pushing their luck with this design. The GTX 295 is known to run very hot. It sits around 70°C at idle. At load the temperature can easily go over 100°C. Touching the heatsink with bare hands is like touching a frying pan in low heat. Either way it's a painful venture for those curious enough to test it out. The cooling fan is loud even at idle and beyond reasonable when running full blast as you can imagine as it tries to prevent a thermal meltdown of the GPU.

Geforce GTX 295


I strive to make my PC as quiet as possible and I made the mistake of buying the loudest video card ever made. At this point I am willing to trade performance for less decibels. I first tried a different thermal compound which did not make any significant improvement. The only thing left to do was to take the heatsink apart. I decided to dissect the heatsink to see how it was constructed and if further modifications could improve the cooling performance.

I used a toaster oven which I repurposed as a solder reflow oven. I made a few modifications to it to better redirect heat where it is needed. It is ugly as hell but works well enough. The only thing it needs is a way to automate the temperature control but that is a project for another time. In the interim I used a thermocouple attached to a multimeter to read temperatures.


With the heatsink on the center rack and top and bottom heating elements doing their magic the solder holding the heatsink together liquified at around 155°C. That was quite lower than I had expected. A typical tin-lead solder melts around 178°C. I am guessing the solder used is of a different mixture. Perhaps, it's the kind with bismuth which lowers the working temperature of solder. It makes sense in an engineering stand point. The copper heat pipes are sealed vessels and made of very thin-walled copper which you can easily crush with bare hands. The lower solder temperature can avoid bursting the heat pipes during reflow. I did notice the heat pipes balloon a little and separate the two halves of the aluminum heatsink.

heat pipeheat pipe


Well, the heatsink appeared to be well constructed. There is plenty of solder that thermally couples the copper plates to the heat pipes and the aluminum fins. I was hoping I would find the opposite given how hot the video card gets. There is not much improvement I could do here with regards to adding more solder.

heat pipesheat pipes


Before calling it quits I did solder a 1mm copper shim on top of the copper plate that heatsinks to the NF200 chipset. This closed the gap between the chip and the heatsink and made it possible to use thermal compound as opposed to thermal tape.

copper shim


I put the heatsink back together by clamping it down and baked it in a conventional oven. I wouldn't want to do this again as it was very involved.

In conclusion, the GTX 295 is a hot card. I don't think it can get any cooler unless a bigger heatsink is used or water cooled. The GTX 295 is pushing the design limits of the heatsink in my opinion. Thermal conduction is not particularly a problem but the thermal capacity is simply not adequate.