I believe he is talking about the difference between GDDR and GDDR2, in which case there isn't much difference.1. I think the best AGP card would be the ATI X850XT.
Or maybe even a 7800GS.
2. DDR2 is faster, and DDR2 will not work on a DDR motherboard
http://www.newegg.com/Product/Product.asp?Item=N82E16814102570
I got a Sapphire ATI Radeon X1600 512MB DDR2 AGPx8 and it works perfectly on my DDR motherboard. Got it for $160.00 Canadian after taxes.
The current best AGP card performance wise is the X850XT PE.Now I know most all of you have PCI-E, but bare with me here. What is the best AGP GPU out there and how much does it cost? And what is the difference between DDR and DDR2? And will DDR2 not work if I have DDR?
they make a 7800GS with a 7900GT core... 24PPL and 512MB of GDDR4