Now is a look at the GPU temperature and system power consumption when the system was idling for two minutes followed by running three loops of Unigine Heaven with a resolution of 1600 x 1200. Of course, this was all automatically facilitated and monitored by the Phoronix Test Suite.
The GeForce GT 520 had the highest GPU core temperature of any of the graphics cards tested (the GPU core temperature though for the Radeon HD 4650 wasn't available since the ATI OverDrive extension hadn't supported it). The EVGA GeForce GT 520 even with its small fan was running 6°C warmer on average than the passively cooled Radeon HD 5450. The GeForce GT 520 was 8°C warmer than the GeForce GTX 460, 13°C warmer than the GeForce GT 240, and 4°C over the GeForce GT 220. The coolest GPU overall was the Radeon HD 6570.
Thanks to the Phoronix Test Suite's support for the Watts Up Pro power meter, we can now deliver AC power consumption results for the system in front of the power supply. To no surprise, the GeForce GTX 460 had consumed the most power, which is not a shock considering the dual PCI-E 6-pin external power connectors that are required for operation. On average while idling and then under Unigine Heaven load, the Sandy Bridge system was going through 106 Watts with the GeForce GT 520. This is in comparison to the system with the GeForce GT 220 going through 109 Watts, the GeForce GT 240 up at 128 Watts, the Radeon HD 5450 at a mere 86 Watts, or the Radeon HD 4650 at a comparable 111 Watts.