So, the performance in ioquake3 games and Nexuiz seems to have the most negative impact with the current state of Mesa and the R300 Gallium3D driver.
To confirm the problem I carried out similar tests from a 32-bit ThinkPad that was running a different Ubuntu release, used a lower-end Mobility Radeon X1400, etc. But it stuck with the Linux 3.2 development kernel, the latest xf86-video-ati/libdrm Git, had the same settings between Mesa tests (including SwapbuffersWait disabled), and just switched out Mesa 7.11.2 for Mesa 7.12-devel Git.
