Thermal Performance

Putting realistic, repeatable load on a GPU to get a decent idea of it's real world thermal output has long been something we've experimented here at bit-tech. We've found that Synthetic benchmarks such as FurMark thrash the GPU constantly, which simply isn't reflective of how GPU will be used when gaming. It's such a hardcore test that any GPU under test is almost guaranteed to hit it's thermal limit, the mark at which the card's firmware will kick, speeding up the fan to keep the GPU withib safe temperature limits.

Conversely, simply leaving a game like Crysis running at a certain point also isn't reflective of real world use. There's no guarantee that the GPU is being pushed as hard as other titles might do, and the load will vary from play through to play through.

Eventually then, we've decided to use 3DMark06's Canyon Flight test as a real world representative, repeatable graphics test. It's a ferociously demanding test, pushing graphics cards to their limit, but also containing peaks and troughs in performance that match real world game play.

As the test is so demanding and GPU limited, we've set 3DMark to run the test at 1280x1024 with 0xAA and 16xAF (enabled in the driver), constantly looping the test for thirty minutes and recording the maximum GPU Delta T (the difference between the temperature of the GPU and the ambient temperature in our labs).



Following it's single PCB redesign just a month ago, the GeForce GTX 295 is now able to run impressively cool, reaching just 21°C above the ambient temperature at idle and peaking at just 44°C above ambient at full load. In comparison the faster single GPU of the GeForce GTX 285 ran noticeably hotter at 27°C and 47°C at idle and peak respectively, notably hotter than it's dual GPU compatriot.

Once again though, the Radeon HD 4870 X2 finishes in last place, belching out a quite ludicrous amount of heat both out the rear of our test case and directly into our system via it's array of cooling plates. Idling at a whopping 45°C above ambient room temperature and peaking with a Delta T of 60°C it's by far the hottest of the three cards.

With the Radeon HD 4870 X2 out of the picture and the GeForce GTX 285 running noticeably hotter than we think a single GPU card should, the GeForce GTX 295 takes this, the final round. Nvidia strolls to an easy 6-2 victory.