The results on the diagram include not only the GPU temperatures, but also the Ambient temperature and the temperature of the hottest voltage regulator component of the three (VRM). The lower the cooler is on the diagram, the higher is the noise level from it:
Against the background of steady “±2-4°C” in our CPU cooler reviews, Accelero Xtreme GTX 280 demonstrates outstanding advantage over the reference GeForce GTX 260 cooling system: 30°C! And this remarkable result is achieved at a much lower noise level. Excellent performance!
Unfortunately, not everything was so unbelievably great. The “bad egg” in this case was the VRM heatsink that proved unable to transfer and dissipate the heat efficiently enough. While for Radeon HD 4870/4890 VRM temperature of 113°C seems more or less typical, then for GeForce GTX 260/280 it is absolutely not. Accelero Xtreme GTX 280 with the fans working at their maximum speed keeps this temperature below 100°C, but above the reading from the reference GeForce GTX 260 cooler. I believe it was the high VRM temperature that wouldn’t let me overclock the card any further with Accelero Xtreme GTX 280 cooler.