Overclocking

For those who have been waiting for this test I won't waste any more of your time : YES, the XFX 7900GS "extreme edition" overclocks like hell.

Without any effort at all we were able to push the core from the standard 480Mhz to 630Mhz on the default cooler. Above 630Mhz, the nVidia control panel refused our overclock. The memory was equally impressive and reached a speed of 840Mhz, up from the standard 700Mhz the card ships with. Actually we could have pushed the memory further, but the nVidia Control Panel wouldn't allow us. For those that want to go further I suggest you download the excellent Powerstrip tool which will allow you to push your card even further. This is of course at your own risck, so be careful not to destroy your brand new hardware while you're at it.

Let's have a look what these overclocks mean compared to a standard 7900GS card :


Now for those who wonder how this excellent overclocking ability is possible, the answer is quite simple : to produce this kind of power the core and the memory have been giving additional voltage to play with. Some of you might know that the standard voltages of the core and memory of a 7900GT are 1.2V and 2.0V respectively. This allows for a core clock of about 540-560Mhz on the 7900GT. The standard 7900GS is in this respect no different : the core and is also fed with about 1.2V and will overclock accordingly.
Now onto the core voltage of the XFX, this is cranked up to a very nice 1.325V. The memory is even fed a quite high 2.2V. With this in mind it's no wonder that these cards overclock so madly. Of course, as in all cases, when you're trying to overclock this card your mileage may vary. : no two cards are the same...


To see what these overclock means in respect to the standard hardware, we've got some generic benchmarks for you too. Have a look at the 3D Mark results :



The 2001 and 2003 tests show clearly the punch that the OC can give you. The 7900GS is able to easily surpass a standard 7900GT in this way. The OC gives you a performance increase of up to 28% in 3D03.



The 2005 and 2006 numbers are even more impressive : the "full" overclock means a performance increase in these tests of over 30%, again easily beating the standard 7900GT.

All these tests were repeated more than once by the way, and the card never showed any sign of overheating, or artifacting in the progress of overclocking. The only slight concern we could mention here is whether the card will have the same lifespan as some other, non-factory overvolted 7900GS's or GT's. This cannot be verified of course, but I do feel we're balancing on the edge of what the stock cooler can handle. I say this with the 7900GTX in mind, which has a far more powerful cooling system at its disposal, and has a standard core voltage of 1.4V, not that much higher than our XFX card...

Let's wrap it all up on the next page ->