Power consumption and heat dissipation of modern graphics cards are most important matters for any user who’s going for an upgrade. In my first report on the subject (see our article called Power Consumption of Contemporary Graphics Accelerators. Part I: Graphics Cards on ATI Chips), I tried my best to accurately measure power-related characteristics of graphics cards on GPUs from ATI Technologies. Today I will do the same with cards on NVIDIA’s GPUs.
My method remains the same: I attach a shunt into each of the power circuits and measure the voltage drop in this shunt. Knowing the value of the voltage drop and the shunt’s resistance, I can calculate the current consumed on each power circuit. Then, from the known current and voltage values, I can easily determine the power consumption.
With graphics cards that have additional power connectors, I attached the shunt into those additional power circuits…
…as well as into the power circuits of the AGP slot. I isolated the appropriate contacts of the AGP slot and send the current directly to the card:
For cards that are only powered through the 3.3v, 5v and 12v lines of the AGP slot, I attached the shunt into these power lines only, of course. For more details about my method of measuring the power consumption of graphics cards, refer to my previous article.
The measurement tools are the same as in the first article: a professional digital multimeter UT70-D from UNI-T…
…and a homemade shunt:
Testbed and Methods
I tested the graphics cards in the following system:
- AMD Athlon 64 3400+ CPU;
- ASUS K8V-SE mainboard;
- 2x512 TwinMOS PC3200 DDR SDRAM, CL2.5.
- Windows XP Pro SP1;
- DirectX 9.0b;
- ForceWare version 61.34.
I measured the power consumption in two modes: “Idle” and “Burn”. There were no running applications in the Idle mode; the screen was displaying the Windows Desktop with a scattering of standard icons in the 1280x1024x32@75Hz display mode. The Burn mode used a scene from Far Cry in 1600x1200 resolution with forced 4x full-screen antialiasing and 16x anisotropic filtering (8x on GeForce FX family cards). I saved the game on the Training level and used this save with all the graphics cards to create the identical test conditions.