I highly doubt it's your ram causing you to be 2000pts lower then u should be.
7800GTX running with 512mb ram 7796 score
bertram928@hotmail.com (if this url doesn't work search by the email address to find it on futuremarks site)
Did you uninstall your old graphics driver from your last card, before you installed your new 7800gtx? Alot of people mistakenly think that you don't have to uninstall the drivers for your previous card when you install the new driver...
It can make a 15-20% difference.
Example: 6800gt and P4 system...
After Uninstalling/Reinstalling drivers...5014
Before...3625
ATI and NVidia drivers fight each other, but getting a different nvidia card (without uninstalling the old drivers) can be just as devestating to your performance. You can't just overinstall new drivers for your graphics card, you must uninstall, reboot, and install new ones. If your old card's drivers are still in, in addition to your new ones, you need to uninstall your current graphics driver (just the nvidia graphics driver...leave the other nforce drivers alone...), shut down, put your old card in, boot up, uninstall your old drivers, shut down, put your new card back in, reboot, and finally, install your new drivers.
Simply uninstalling your old drivers may not work, or may not work completely. You might see a % increase, but not as good as you would if you uninstalled it properly.
If your old card was an nvidia card and you didn't uninstall the old drivers before installing new ones: then simply uninstalling the driver you have in there currently (and reinstalling the new drivers), should do the trick...
-otherwise you may have to go through the earlier steps, only this time, uninstall your current graphics driver (just the nvidia graphics driver...leave the other nforce drivers alone...), shut down, put your old card in, boot up, reinstall your old drivers (since they were improperly uninstalled...), reboot, uninstall your old drivers, shut down, put your new card back in, reboot, and finally, install your new drivers.
Or...It could just be that you have a lot of crap running in the background holding you back. If you ran it with f@h running for instance (no pun intended), that would account for the lower then avg score.
With all that said...your gaming is severely limited (in terms of new games...) by that 512... There are two games out now that i personally play that use more then 1024mb to play (and almost every game i play uses more then 512...)...EQ2 and BF2. I've never seen where BF2 uses more then 850mb or so, but it runs sooo much smoother with 2048 then with 1024. EQ2 also no longer lags in heavy zones as tons of stuff are loaded in (but i have ctrl-alt-del to chk the processes, and it does use more then 1024mb during gameplay with the way i have it setup).