|PowerColor Radeon HD 6870 PCS+ Video Card|
|Reviews - Featured Reviews: Video Cards|
|Written by Bruce Normann|
|Tuesday, 11 January 2011|
Page 18 of 20
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 turning "green". I'll spare you the powerful marketing hype that gets sent 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.
Take a look at the idle clock rates that AMD programmed into the BIOS for this GPU; no special power-saving software utilities are required. This is not the bleeding edge of what the industry is doing today, in terms of speed throttling to save energy, but its close enough. I was running Catalyst Control Center at the time with Overdrive, so the memory clock is higher than the absolute minimum of 81 MHz. This is one of the reasons why a factory overclocked card is sometimes better than a DIY approach. Whether you're using the chip maker's software to overclock the GPU, like AMD's Catalyst Control Center, or a vendor's application like MSI Afterburner, there is often the possibility that the idle clocks will be affected. If you're running a multi-GPU setup, it gets even more complicated. Suffice it to say that the surest way to get the lowest possible idle power is to use a factory overclocked card and run it without any additional monitoring and control software.
To measure isolated video card power consumption, I used 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:
* Results are accurate to within +/- 5W.
The PowerColor PCS+ HD 6870 1GB GDDR5 Video Card pulled 46 (168-122) watts at idle and 198 (320-122) watts when running full out, using the test method outlined above. The PowerColor PCS+ HD 6870 is on par with the first generation of 40nm ATI cards, as far as power consumption at load, and a little better at idle. The reduced idle clocks play a part in that, and the factory overclock provides the opposite effect in the slightly higher-than-reference power draw under fully loaded conditions.
We've all become used to the low power ways of the newest processors, and there's no turning back. BTW, just because you asked... GPU-Z reported a GPU voltage of 0.945V at idle, 1.195V in 2D mode, and 1.195V in full 3D mode.
Next, I'll offer you some final thoughts, and my conclusions. On to the next page...