ATI HD4870 & HD4850 Crossfire Performance Review

Power Consumption

For this test we hooked up our power supply to a UPM power meter that will log the power consumption of the whole system twice every second. In order to stress the GPU as much as possible we once again use the Batch Render test in 3DMark06 and let it run for 30 minutes to determine the peak power consumption while letting the card sit at a stable Windows desktop for 30 minutes to determine the peak idle power consumption.

Please note that after extensive testing, we have found that simply plugging in a power meter to a wall outlet or UPS will NOT give you accurate power consumption numbers due to slight changes in the input voltage. Thus we use a Tripp-Lite 1800W line conditioner between the 120V outlet and the power meter.


While performance of these cards was simply astonishing, we were gobsmacked by the amount of power these cards need. The load numbers are acceptable considering there are a pair of cards working behind the scenes but it is the idle power consumption that had us shaking our heads. It seems like ATI’s much-ballyhooed PowerPlay feature is completely out to lunch in another dimension. Sorry ATI, but when the idle power consumption of your higher-end Crossfire solution comes close to matching the full load power requirements of a 9800GTX, you know there is an issue somewhere. Especially in this day and age of cutting down on one’s carbon footprint.

So, what kind of power supplies would we recommend. Well, considering these tests put full load on the graphics card with very little load on the rest of the system we would recommend a quality 700W or higher power supply for a HD4870 Crossfire system and a 600W or higher PSU for a HD4850 Crossfire setup.