X-bit labs

NVIDIA GeForce 7800 GTX: New Architecture Exposed (page 7)

Category: Video

by Alexey Stepin

[ 06/22/2005 | 12:52 PM ]

Noise, Overclocking, 2D Quality

The GeForce 7800 GTX behaves just like its predecessors on the system’s start. The fan of its cooling system works at its fastest and noisiest until the OS is booted. After that, however, the fan is automatically slowed down, and the noise diminishes. This graphics card is subjectively quieter than the GeForce 6800 Ultra or GT, and it is quite comfortable to work in the booted OS. A SLI configuration of two GeForce 7800 GTX is louder, of course, but the noise is bearable, especially if you compare it to the noise from two GeForce 6800 Ultra. The fan speed control system never made the fan work at its full speed throughout our tests. It means NVIDIA’s improved reference cooler does its job well. Unfortunately, you can’t put a noiseless cooler like Arctic Cooling NV Silencer 5 on the GeForce 7800 GTX because the memory chips on the reverse side of the PCB would be left without any cooling. So, we have to wait for a special version of the cooling device.

We had little hope for good overclocking with the new GeForce. A chip made of 300 million transistors and on 0.11-micron tech process without special dielectrics can’t be expected to have a high overclocking potential. Take the RADEON X800 XL as an example: this chip can seldom speed up above 420-430MHz. We were wrong, however, in this particular case. We managed to overclock the GPU on our sample of the GeForce 7800 GTX to 490MHz. That is, we achieved a 60MHz frequency gain instead of the expected 20-30MHz. The memory performed worse, overclocking to 610 (1220) MHz only, but it’s natural for 1.6ns chips that had already been working at their rated frequency. Our second sample of the GeForce 7800 GTX overclocked almost like that, too. To 480/620 (1240) MHz frequencies, to be exact.

The quality of the 2D image was excellent in all resolutions up to our monitor’s maximum of 1800x1440@75Hz. We checked this out on a 21” CRT monitor Dell P1130 which differs from the older Dell P1110 in the design of the case. Well, we didn’t expect 2D quality other than excellent from a top-end graphics card like the GeForce 7800 GTX.