X-bit labs

Two for One: Nvidia's Dual-Chip GeForce 7950 GX2 Reviewed (page 8)

Category: Video

by Alexey Stepin , Anton Shilov

[ 06/09/2006 | 06:01 PM ]

Overclocking and 2D Quality

We tried to overclock GeForce 7950 GX2 to find out its frequency potential. Before we started our experiments we expected to achieve pretty good results for the graphics chips and not very good results for the memory, which featured 1.4ns access time – much lower than 1.1ns in GeForce 7900 GTX or Radeon X1900 XTX. As a result, we managed to get our graphics card to work stably at 590MHz chip frequency. The cooling system was definitely not the most efficient one, besides, the air intake for the bottom fan was slightly hindered, so the additional 90MHz we managed to get can be considered a pretty good result. These additional 90MHz should ensure s a pretty noticeable performance improvement for our GeForce 7950 GX2, at least in those tasks where the graphics memory will not turn into a limiting factor.

As for the memory, it turned out a real disappointment, as it worked fine only at 670 91340) MHz, i.e. it didn’t even reach the nominal value of 700 (1400) MHz. We even checked the contact between the memory chips and the heatsink foot: it was perfect. So, we believe that this low result could have been caused by not the best memory chips layout on the GeForce 7950 GX2 PCB. The memory chips working at such high frequencies are usually located in half circle around the GPU. On our card the engineers were probably trying to save some room, so they put the memory chips in an L-shaped manner. As a result, the connection between the chips and the GPU turned out far from optimal, which may have had negative influence on the memory stability at high frequencies.

As for the 2D image quality demonstrated by GeForce 7950 GX2, we cannot complain about anything, even in the maximum resolution mode of our lab monitor – 1800x1440@75Hz. The picture was crisp and clear in 1600x1200@85Hz. Note that in the multi-GPU mode when both graphics cores are involved, the card allows connecting only one display. The second DVI-I is disabled in this case. If you would like to use multi-monitor configurations, the card should be switched into multi-monitor mode. In this case all the standard Nvidia nView features will still be supported, however, only one GPU will be working and the gaming performance will drop down significantly.