Starting with OpenArena shows that the R500 Mesa graphics in Fedora 13 Beta are actually running slower than they were in Fedora 12. This may be partially due to the extra debugging options found within Fedora Goddard's development kernel, but not entirely as you can see at the higher resolutions there is a smaller delta than at the lower resolutions. With the classic Mesa R500 driver, neither Fedora 12 nor Fedora 13 Beta was really playable with this open-source game at 1280 x 1024 or higher.
Similar to OpenArena, with World of Padman Fedora 13 Beta started out running much slower than Fedora 12. However, as the resolution increased, the delta closed in. At 1280 x 1024 and 1400 x 1050, the frame-rate in this ioquake3-powered game was virtually the same between the two Red Hat Fedora releases.
Similarly, with Urban Terror, Fedora 13 Beta was at a performance disadvantage to Fedora 12, but at the higher resolutions, the difference in frame-rate was much smaller.