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.
This section discusses power consumption for the NVIDIA GeForce GTX 780 video card, which operated at reference clock speeds. Our power consumption results are not representative of the entire GTX 780-series product family, which may feature a modified design or factory overclocking by some partners. GeForce GTX 780 requires an 8-pin and 6-pin PCI-E power connections for normal operation, and will not activate the display unless proper power has been supplied. NVIDIA recommends a 600W power supply unit for stable operation with one GeForce GTX 780 video card.
In our test results the GeForce GTX 780 consumed a mere 10W at the lowest idle reading, and 275W under full load with fan operating at 100%. NVIDIA’s average TDP is specified as 250W. This positions the GTX 780 among the least power-hungry top-end video cards we’ve tested under load, but much more impressive that it’s achieved by a flagship GTX-series product. If you’re familiar with electronics, it will come as no surprise that less power consumption equals less heat output as evidenced by our thermal results below…
GeForce GTX 780 Temperatures
This section reports our temperature results subjecting the video card to 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:
|Video Card||Ambient||Idle Temp||Loaded Temp||Max Noise|
|ATI Radeon HD 5850||20°C||39°C||73°C||7/10|
|NVIDIA GeForce GTX 460||20°C||26°C||65°C||4/10|
|AMD Radeon HD 6850||20°C||42°C||77°C||7/10|
|AMD Radeon HD 6870||20°C||39°C||74°C||6/10|
|ATI Radeon HD 5870||20°C||33°C||78°C||7/10|
|NVIDIA GeForce GTX 560 Ti||20°C||27°C||78°C||5/10|
|NVIDIA GeForce GTX 570||20°C||32°C||82°C||7/10|
|ATI Radeon HD 6970||20°C||35°C||81°C||6/10|
|NVIDIA GeForce GTX 580||20°C||32°C||70°C||6/10|
|NVIDIA GeForce GTX 590||20°C||33°C||77°C||6/10|
|AMD Radeon HD 6990||20°C||40°C||84°C||8/10|
|NVIDIA GeForce GTX 650 Ti BOOST||20°C||26°C||73°C||4/10|
|NVIDIA GeForce GTX 650 Ti||20°C||26°C||62°C||3/10|
|NVIDIA GeForce GTX 670||20°C||26°C||71°C||3/10|
|NVIDIA GeForce GTX 680||20°C||26°C||75°C||3/10|
|NVIDIA GeForce GTX 690||20°C||30°C||81°C||4/10|
|NVIDIA GeForce GTX 780||20°C||28°C||80°C||3/10|
As we’ve 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 low idle temperature, and translates into modest full-load temperatures. While NVIDIA’s reference design works exceptionally well at cooling the GK110 GPU on GeForce GTX 780, consumers should expect add-in card partners to advertise unnecessarily excessive over-cooled versions for an extra premium. 80°C after ten minutes at 100% load is nothing at all, and is nowhere close to this card’s 95°C thermal threshold.