|NVIDIA GeForce GTX 680 Graphics Performance|
|Reviews - Featured Reviews: Video Cards|
|Written by Olin Coles|
|Thursday, 22 March 2012|
Page 14 of 15
VGA Power Consumption
In this section, PCI-Express graphics cards are isolated for idle and loaded electrical power consumption. In our power consumption tests, Benchmark Reviews utilizes an 80-PLUS GOLD certified OCZ Z-Series Gold 850W PSU, model OCZZ850. This power supply unit has been tested to provide over 90% typical efficiency by Chroma System Solutions. To measure isolated video card power consumption, Benchmark Reviews uses the Kill-A-Watt EZ (model P4460) power meter made by P3 International. In this particular test, all power consumption results were verified with a second power meter for accuracy.
The power consumption statistics discussed in this section are absolute maximum values, and may not represent real-world power consumption created by video games or graphics applications.
A baseline measurement is taken without any video card installed on our test computer system, which is allowed to boot into Windows 7 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 before taking the idle reading. Our final loaded power consumption reading is taken with the video card running a stress test using graphics test #4 on 3DMark11. Below is a chart with the isolated video card power consumption (system without video card subtracted from measured combined total) displayed in Watts for each specified test product:
* Results are accurate to within +/- 5W.
The GeForce GTX 680 accepts two 6-pin PCI-E power connections for normal operation, and will not activate the display unless proper power has been supplied. NVIDIA recommends a 550W power supply unit for stable operation with GTX 680, which should include both required 6-pin PCI-E connections without the use of adapters.
If you're familiar with how electronics function, it will come as no surprise that less power consumption equals less heat output, evidenced by our results below...
GeForce GTX 680 Temperatures
This section reports our temperature results with the GeForce GTX 680 under idle and maximum load conditions. During each test a 20°C ambient room temperature is maintained from start to finish, as measured by digital temperature sensors located outside the computer system. GPU-Z is used to measure the temperature at idle as reported by the GPU, and also under load. Using a modified version of FurMark's "Torture Test" to generate maximum thermal load, peak GPU temperature is recorded in high-power 3D mode. FurMark does two things extremely well: drives the thermal output of any graphics processor much higher than any video games realistically could, and it does so with consistency every time. Furmark works great for testing the stability of a GPU as the temperature rises to the highest possible output.
The temperatures illustrated below are absolute maximum values, and do not represent real-world temperatures created by video games or graphics applications:
As we've already mentioned on the pages leading up to this section, NVIDIA's Kepler architecture yields a much more efficient operating GPU compared to previous designs. This becomes evident by the extremely low idle temperature, and the modest loaded temperature. What's even more impressive than these results is how quiet GeForce GTX 680 operates, barely changing levels from silent to almost silent as it reaches full load. Even with an open computer case exposing the video card, it's difficult to hear the blower fan make any noise at all. While NVIDIA should be proud of updating their product line with the fastest graphics processor on the planet, I'm happy they also made it one of the most quiet-running flagship video cards ever tested.