To test our graphics cards for both temperatures and power consumption, we utilize OCCT for the stress-testing, GPU-Z for the temperature monitoring, and a Kill-a-Watt for power monitoring. The Kill-a-Watt is plugged into its own socket, with only the PC connect to it.
As per our guidelines when benchmarking with Windows, when the room temperature is stable (and reasonable), the test machine is boot up and left to sit at the Windows desktop until things are completely idle. Once things are good to go, the idle wattage is noted, GPU-Z is started up to begin monitoring card temperatures, and OCCT is set up to begin stress-testing.
To push the cards we test to their absolute limit, we use OCCT in full-screen 2560×1600 mode, and allow it to run for 30 minutes, which includes a one minute lull at the start, and a three minute lull at the end. After about 10 minutes, we begin to monitor our Kill-a-Watt to record the max wattage.
Can I hear a “Whoa.” just one more time? The HD 5770 deserves it. Compared to the HD 4870, the HD 5770 runs a staggering 22°C cooler at idle, and 9°C cooler at max load. Likewise for the power consumption, the HD 5770 in the same comparison shaves the idle power down 41W and its load by 93W. These are hardly small differences.