How to compare g/cards??

I may be a bit slow here but can someone tell me how I can compare my 7800GTX 256mb to 9800GT 1gig. I cant find the 9800GT listed on the charts, only the GTX. Is there a reason for this or am I missing something...?

Find a link between modern generation and old generation card. Here it's 8600gt. See how your card fares against 8600gt and how 8600gt fares against 8800gt. Also, trickier it gets because while old cards can perform as well as newer ones in older games, it may be quite below in modern games.
Tomshardwares hierarchy chart would also give you idea if you couldn't find exact comparisons.
http://www.tomshardware.com/review [...] 965-6.html
Here it shows 7900gt is same tier as 7800gtx. Google the comparisons.
You'd get about 1.7-2 times more performance.

ok, its a hit and miss exercise but I have to put a lot of faith in these posts I read in the forums. Hopefully buying tomorrow! Thanks-)

Also, if you wanted to compare performance then you have to look at review and benchmark of both cards on the same website. However, the website must have a review or benchmark for both cards. Comparing video cards by using 2 different websites is not always a good idea because sometimes 2 different websites or 2 different testers use different Test Setup like different motherboard or different CPU while testing the video card. For example, let's say that Bittech.com might use Gigabyte GA-P35-DS4 with a Core 2 duo CPU to test Geforce 7800 GTX and Techpowerup.com might use ASUS P6T-Deluxe with Core i7 Extreme 650 to test Geforce 9800 GT so this does not make a good valid comparison because both ASUS and Gigabyte motherboard and 2 different CPUs might give a different test result of performance. Sometimes you also have to look at the date of when it was tested and what driver version they use when they made the benchmark performance because sometimes, different driver version could give a different test result of performance. To check the date, just simply check when the review/benchmark was posted on the website by the author or check it on the benchmark page (if it says) and the test/system setup page or the benchmark page might tell you the driver version.

This is the kind of thing I've been doing for a long long time but it is not easy because sometimes the same website does not have review/benchmark of 2 cards that I wanted to compare and sometimes they use different test setup.