Temperature, Power Consumption and Overclocking
The old GeForce 8800 GT was, quite literally, a hot card. Running at 83 degrees Celsius, it was in dire need of a better cooler, and that was why we were particularly concerned about the Zotac 9800 GT AMP! Edition, seeing that it was the most highly overclocked, and yet still sporting what seems to be a reference cooler. Luckily, it topped out at 70 degrees Celsius, not cool, but considering its clock speeds and the fact that it doesn't have any fancy dual-slot cooler, we can't complain.
The ATI cards were pretty warm too, with the newer Radeon HD 4850 topping out at 72 degrees Celsius, and the older HD 3870 at 65 degrees.
The Gigabyte, Palit and ASUS cards which were all sporting radical coolers performed rather well. The Gigabyte and Palit coolers were particularly impressive, as they were able to bring operating temperatures down to around 55 degrees Celsius.
Here, the ATI Radeon HD 4850 was by far the most power hungry card. It was measured at 350W at load, almost a good 100W more than any other card we have here.
Looking at the NVIDIA contingent, we can see that the two coolest cards were also the most power-hungry. Clearly, running these special coolers requires quite a substantial amount of juice. In comparison, the Zotac 9800 GT AMP! Edition and ASUS Matrix required less power. In the case of the ASUS, it certainly looked at first glance that the self regulating "Hybrid Super Engine" was working, but we can't say for sure without doing more thorough testing (which we may explore with a proper retail version in the future).
Next, we took the five NVIDIA cards and pushed them to their absolute limits by overclocking them, and quite amazingly, all four 9800 GT cards topped out at about 750MHz at the core. Memory was a trickier affair, with the Zotac and Palit cards topping out at almost 2300MHz, whereas the Gigabyte 9800 GT could only manage 1860MHz. For the case of the ASUS Matrix, we couldn't even tweak the memory at all, as it would crash before completing the benchmark test. Certainly, it was justifying its prototype sample billing.
As for the older GeForce 8800 GT, despite using the same G92 core as the GeForce 9800 GT, it maxed out at only 660MHz and 1900MHz, which represents a rather insubstantial 60MHz gain at the core and a 100MHz gain at the memory.