Overclocking the Viper 770

If I haven't emphasized it enough already, let me say it again: clock rate is king.

If the Viper 770 Ultra is fast at 150/183, wouldn't it be even faster at 175/200, the original speed that Diamond demonstrated the card at back in March? You bet. It's ethically questionable that Diamond saw fit to demonstrate their card at the higher speed, but were unable to ship it at that same speed.

Luckily, Diamond hasn't completely abandoned us. The ability to overclock the core and memory speeds of the V770 is built right into the Diamond drivers. And if, like me, you prefer to run the more up to date Nvidia reference drivers, there are several freeware overclocking utilities that work on the TNT and TNT2 cards.

So, how high does it go? Well, that's an interesting story. Video cards are a lot like modern CPUs, having extremely complex designs with millions of transistors. If you follow overclocking sites, you'll notice that the Intel Celeron 300a CPU had an irresistible cachet among overclockers, because it could frequently achieve an overclocked speed of 450mhz-that's an astonishing 50% overclock! By that logic, you would expect the virtually identical similar Celeron 400a to be overclocked to 600mhz, right? Well, not exactly.

The Celeron CPU core, while identical in both the 300mhz and 400mhz versions, has a practical internal speed limit that is largely determined by its architecture and design. That limit appears to be about 500-550 megahertz by most estimations. No amount of cooling or tweaking, short of below-zero supercooling, will coax the chip to run any faster. While it may seem foolish to purchase a 300mhz processor when you can buy a 400mhz processor for almost the same price, there is something intangible you get with the slower processor: headroom. The 300mhz processor is operating nowhere near its internal limits, whereas the 400mhz processor is much closer to that limit.