Sapphire Radeon HD 5870 Vapor-X

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.

From a temperature standpoint, the Vapor-X excels. In fact, despite being immensely more powerful, it’s cooler than NVIDIA’s GTS 250, and just a wee bit hotter than the HD 4770. On the power side, once again, the HD 5870 is far more powerful than the HD 4890, yet uses 1W less on average at full load. Where the card really shines, though, is in its idle power, which is a full 34W less than the HD 4890.