Which card would you recommend between these two;
HD 2900 Pro 512MB
Both are available for ~£100 if you dig around but finding a direct performance comarison is a bit harder. I like to tinker with cards so overclocking headroom would be helpful and it will be used for COD4 @ 1680*1050.
Thanks for ur advice
The 8800gt 256 is slower than the 3850 in some games, as cards really need 512 megs nowadays. The 3850 512 is slower than the 3870, which is basically on par with the 2900XT. So, the 2900 Pro is probably closer to the 3850 512 in speed. Without a long search for reviews to find benchmarks, that's the score as the ATI cards compare between generations.
So, the 2900Pro should be faster than the 8800GT due to more RAM. The difference might be less than 10 fps. Okay, I just got the idea to check the "What about the other card?" page on the Best Gaming Graphics: January 2008, and the two cards are in the same category:
Nvidia cards: 8800GT 256; 8800GTS 320 equal to each other and equal to the X2900 Pro and the 3850 ATI, which are equal to each other in capabilities.
I admit, I don't overclock CPU's or GPU's. I'm a bit conservative about that, but you could use the general equivalency given here at Tom's as a basis for overclocking comparisons. For that you'd need to check at Tom's, Anandtech, Xbit Labs, Sharkey's etc. for reviews focused on overclocking. Usually when a new card comes out there's a quick review that touches upon the headroom for overclocking.
If you can, spend a bit more and get a 3850 512, it has better thermals than either the 2900 Pro or the 8800GT 256.
The 256mb 8800GT really suffers for having half the memory of the 512mb gt. If you get the pro it can be overclocked into the low 800's on the gpu and up to around 950(1900) on the ram on the stock cooler. What I mean is a 256mb 8800gt will always be badly handicaped by the low amount of memory but the 2900pro can approach 512mb 8800gt performance and beat any factory oc'd 3870 with overclocking. I bought a pro with the express intention of overclocking the sh#t out of it at some later date.