Post a GPU-Z screenshot of both GPU's, if you would.
Oh, BTW, a lot of these Benchmarks are posting with higher OC'ed i5's. While it might not bottleneck most games, it still increases your score and some games still improve the FPS with the CPU OC'ed all the way to 4.0.
But I highly doubt that, so why are those benchmarks different?
Two major differences. The benchmarks I saw that hit 25k has an i7 OC'ed to 4.2Ghz. Say what you will about your i5 not bottlenecking all you want, but CPU speeds makes a difference and makes a huge difference when you are at 1280x768, which is resolution used on the performance setting.
The other difference is newer drivers have improved performance some.
I oc'd My i5 750 to 4.0GHz and there was no difference (~10 points - fluctuation) compared with 3.2GHz.
Which tab of GPU-Z? Which Graphics card? etc.
The tab at the bottom left that should have a drop down for both cards. Make sure the bus interface is running at x16 2.0, or at least x8 2.0. Most cases x4 2.0 will kill performance by as much as 40%.