VGA Power Consumption

Life is not as affordable as it used to be, and items such as gasoline, natural gas, and electricity all top the list of resources which have exploded in price over the past few years. Add to this the limit of non-renewable resources compared to current demands, and you can see that the prices are only going to get worse. Planet Earth is needs our help, and needs it badly. With forests becoming barren of vegetation and snow capped poles quickly turning brown, the technology industry has a new attitude towards suddenly becoming "green". I'll spare you the powerful marketing hype that I get from various manufacturers every day, and get right to the point: your computer hasn't been doing much to help save energy... at least up until now.

To measure isolated video card power consumption, Benchmark Reviews uses the Kill-A-Watt EZ (model P4460) power meter made by P3 International. A baseline test is taken without a video card installed inside our computer system, which is allowed to boot into Windows and rest idle at the login screen before power consumption is recorded. Once the baseline reading has been taken, the graphics card is installed and the system is again booted into Windows and left idle at the login screen. Our final loaded power consumption reading is taken with the video card running a stress test using FurMark. Below is a chart with the isolated video card power consumption (not system total) displayed in Watts for each specified test product:

The Radeon HD 4870 X2 is already no stranger to high power bills, based on the fact that it tops our chart for power consumption under load. Sapphire actually improves efficiency over the reference design, primarily as a result of lower operating temperature. This seems odd when you consider how the Atomic 4870 X2 requires an 8- and 6-pin power source, compared to the reference Radeon HD 4870 X2 that requires (only) two six-pin PCI-Express power connections. This may leave some middle-market enthusiasts and lower-end gamers in search of a new power supply feed this Atomic reactor the 256 W it consumes under load.

Most enthusiasts make the mistake of associating a smaller die process with an improved power efficiency. Clearly, the downside to the 55 nm RV770 GPU is it's lack of energy efficient operation. Putting two together on the same PCB doesn't double the consumption of a single Radeon HD 4870, but it sure does try. The power consumption measured under full load doesn't match the performance, but it certainly matched heat output. The idle power draw is extremely high, which is uncommon since emphasis is usually placed on idle/standby mode efficiency and conservation.

Taken as a whole the idle stand-by power consumption is pretty unforgivable, especially since this the condition your equipment will be in the majority of the time. While loaded power consumption actually less than the overclocked GeForce GTX 280, the price paid to your utility company for gaming will end up being about the same as any other video card. With this in mind, it would really make sense for AMD/ATI to design one of these dual-GPUs to power-down in 2D and low-3D modes. Once upon a time, the computer and gaming consoles seemed like an inexpensive alternative to arcade gaming... but that was before energy costs soared through the roof.

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