Results of Overclocking

Overclocking Celeron CPUs is, in many ways, identical to TNT2 overclocking. Sometimes, having a high default clock rate is not an advantage. The Viper V770 is no exception to this rule.

Here are my overclocking results with all the TNT2 cards I have encountered to date:

LeadTek S320-II 32mb. Default 125/150, Overclock 160/150
MaxiGamer Xentor 16mb. Default 135/166, Overclock 165/180
Viper V770 32mb. Default 125/150, Overclock 165/185
Viper V770 Ultra 32mb. Default 150/175, Overclock 160/200

After personally using three different TNT2 chips that all go to 160mhz with total stability in hours of Quake 3 gameplay, I feel very confident in making the following assertion: I can practically guarantee that any well made TNT2 card will overclock to ultra levels. There are a few things to look out for, though.

1. Memory speeds
Look for 6ns memory, minimum, which should get you to 175mhz without a problem. One advantage of the Viper 770 Ultra is that it has 5.5ns memory over the 6ns memory on the regular Viper, so you can expect better memory overclocking results.

The LeadTek S320-II has relatively slow 7ns memory; 7ns memory works out mathematically to (1000/7) or 143mhz. As you can see, the memory on the Leadtek TNT2 card is hardly overclockable at all since it is already running so close to its theoretical limit. Don't expect miracles from the memory on your video card, and know what speed it is rated at before touching that overclocking slider.

2. Cooling
The Viper V770 only comes with a heatsink, whereas the Viper 770 Ultra comes with a heatsink and fan. This is true of most TNT2 cards. If you want to overclock a card without a fan, you absolutely must add cooling to the card before you do anything else. Radio Shack sells a 486 fan that fits perfectly into most video card heatsinks, but this will end up blocking the PCI slot below the AGP card. It may be worth purchasing the Viper 770 Ultra to get the snazzy low-profile integrated heatsink and fan, if slots in your case are at a premium.

3. OEM vs. Retail
Diamond is a huge OEM dealer. There may very well be a difference in memory and chip quality between retail packaged Viper 770 cards and the OEM versions, so beware. It is typical for OEM equipment to deviate from retail equipment in significant ways. Don't assume that excellent retail overclockability translates into cheap OEM overclockability, even for the exact same model of card.