I just bought a ZOTAC GeForce GT 640 ZONE Edition fanless GPU.
It's a card that was not reviewed well by SPCR. It was said to run over 100° C. when given a torture test.ZOTAC GeForce GT 640 ZONE Edition fanless GPU review by SPCR, September 2012
My system contains one exhaust fan 92mm running at low speed unless the CPU heats up.
It contains one intake fan 80mm running at low speed.
The CPU heatsink is a Scythe Ninja2 with 120mm fan running at ~750 rpm.
The PSU is a Tagan 330W with 2x 80mm in push-pull.
The only thing that sets my system apart is that the CPU fan is located straight above the graphics card.
ZOTAC modified the card as was reviewed. The heatsink is now smaller and no longer runs across the back. Also it just contains 2 heatpipes instead of 3.
Strange thing is the heatsink still contains holes for a 3rd heatpipe. Seems they have been cutting production costs on this unit.
I bought the card precisely because it had a heatsink on the back. Bummer.
I'm running a FurMark Burn-in test, these are my results, case closed:
After 16 minutes I add Prime95 torture test for the CPU. Exhaust fan ramps up to 1400 rpm.
20:00 cpu: 55°, gpu: 65°
30:00 cpu: 58°, gpu: 65°
When I first ran the FurMark test for a long time, Windows shut down suddenly to "protect the system". I can only assume it was a hardware instability.
My harddisk ran quite hot and SMART doesn't seem to work on it, so I took the liberty of removing a 5.25" front plate to give it some air.
Still, I can't get this GPU to exceed 65 degrees.