Leaving quality issues aside, GeForce 6800 GT is clearly a more powerful accelerator than X800 PRO. If they were sold at equal prices, the former would be much more preferrable as it is faster in most tests. But there are not many places where the difference is really huge.

However, there are too few 6800 cards for the moment, and what price will be for GT is anyone's guess. Considering that GeForce 6800 Ultra are sold at USD 700, chances are GT will be only a little cheaper. But anyway, it will certainly be more expensive than USD 500-520 which is the current price for X800 PRO in Russia. So, the price will be a decisive factor.

As for power requirements, GT has them lower than Ultra, so 400-420W or perhaps even 360W will be quite enough. The one-slot design makes the card fit for any case, and only a longer PCB may hinder the card's installation in the barebone. Also noteworthy is the card's heating, as its core temperature reached 80°C even when the cover was removed.