If you're ever curious in the future and don't want to wait for someone to post on a forum, NewEgg.com maintains an Excel spreadsheet on most video card models and their specifications.
Physically the 7800GTX GPU is 25MHz faster and the RAM is 200 MHz faster at stock speeds, and the GTX has 4 more Pixel Pipelines (though I think those pipes are on the 7800 GT as well, just not enabled).