Yeah, I have a feeling its that only, definietly. I mean, the cards all have the same software, etc built in, with minor changes, but nothing that'd make a game really run differently on one card to another.
Well there could be something to the fact that the game is made to run at like XXX.XX clock speeds and XX pipelines. And that making it more efficient for the game to run on the specifized hardware.
I don't want to run it on lower settings, it rules like this! I just cannot understand why it wont run as well on lower settings as it does on high. Considering i don't think my computer should be able to handle high settings at around 30fps. Just makes it hard for me to understand it, considering i was intending to upgrade my GPU.
By the time you upgrade (I wish I didn't from my Radeon 9800PRO as it was fine for nowadays games) new games will be coming out that will be using the next gen effects and stuff, like Direct X 10 (I know it may still be a while, but your card will last until then)