To test the temperatures of the Sapphire Vapor X 5750 I fired up FurMark 1.70 and GPUz. Running FurMark at a resolution of 1024x768 was more than enough to bring the work load to 100%
All temperatures were taken with the fan control on auto. Starting out at 51 degrees is comparable to where the reference 5750 started out. Under full load, however, is a different story. The reference card jumped up to 74 degrees while the HIS Radeon HD5750 heated up to 73 degrees. Obviously it's not a direct comparison since testing conditions vary between two different writers but you can find the details on the reference card here.
Benchmark Results: The fact that the Diamond Radeon HD5750 got as hot as it did was a little disappointing to me. Granted, once it got to that temperature it held steady and was nowhere near dangerous to the card. Although, I had higher hopes for the temperature because it is using a third party cooler from Arctic Cooling.