GeForce 7800 GTX 512: The Battle for Watts

Of course, we could not omit to check such an important parameter of the GeForce 7800 GTX 512 as power consumption. The ordinary GeForce 7800 GTX consumes about 80W when a heavy 3D application is running. The new product from NVIDIA works at higher frequencies and has two times the amount of memory, so we were curious to see if it eats more than 100W and is more voracious than the current “leader?ATI RADEON X1800 XT 512MB.

We measured the power consumption of the card on a specially configured testbed:

• Intel Pentium 4 560 CPU (3.60GHz, 1MB L2 cache)
• Intel Desktop Board D925XCV
• PC4300 DDR2 SDRAM (2 x 512MB)
• Samsung SpinPoint SP1213C hard disk drive (Serial ATA-150, 8MB buffer)
• Microsoft Windows XP Pro SP2, DirectX 9.0c

The graphics card was put to test by running the third 3DMark05 subtest in a loop in 1600x1200 resolution with enabled 4x FSAA and 16x AF. We made the measurements by means of a digital multimeter Velleman DVM850BL (its 0.5% accuracy is sufficient for our purpose). And here are the results:

The power consumption of the new graphics card proved to be lower than we had expected and exceeded the 100W mark only in the overclocked mode. The much higher frequencies and the larger amount of graphics memory of the GeForce 7800 GTX 512 come at a reasonable tradeoff of only 14 extra watts of consumed power. The RADEON X1800 XT 512MB with its 112W consumption still remains the single graphics card that requires more than 100W of power in its default operational mode. We think the lower memory voltage contributed to the result of NVIDIA’s new product (1.8 volts against the RADEON X1800 XT 512MB’s 2.0 volts).

We also measured how much power the GeForce 7800 GTX 512 needed when idle and in 2D tests of Futuremark PCMark05. The Idle consumption of the card was about 29-32W, depending on the running application. The consumption grew up to 53.3W in PCMark05 because the card’s frequency control system thought that a 3D application had been launched and increased the GPU clock rate from 275 to 550MHz.

Generally speaking, a power consumption of less than 100 watts is an excellent parameter for such an advanced device, which is another confirmation of the clever design of the G70 processor as well as of G70-based graphics cards. If you are going to become an owner of a GeForce 7800 GTX 512, you will of course need a high-quality and expensive power supply with an up to 450W wattage. But we think it won’t be a big problem to you, if you are ready to spend as much as $649 for a graphics card alone. And if you are into SLI configurations and want to assemble one out of two GeForce 7800 GTX 512 cards, you will have to have a power supply capable of yielding a sustained 500-550W and more.