Issued as a stable release update to Ubuntu 12.04 LTS last week was Unity 5.12. Aside from offering some minor usability enhancements and various fixes, Unity 5.12 should fix some of the OpenGL performance problems that many users have experienced -- and multiple Phoronix articles have noted the OpenGL performance slowdown -- so here's some tests seeing how Unity 5.12 now affects the OpenGL gaming performance.
Unity 5.12 (and Unity 2D 5.12 is also available, but there's no performance changes there) was pushed out last week as an update to Ubuntu 12.04 LTS and it's also the version currently found in the Ubuntu 12.10 development repository. The main change to Unity 5.12 that I find the most exciting -- and that most Phoronix readers will too -- is that "Fix major performance regression-regression due to rebinding FBO's much more often than is required." While Compiz is still causing some OpenGL performance slowdowns, there is this now-fixed bug in Unity that caused performance regressions due to rebinding OpenGL Frame Buffer Objects (FBOs) more than what was needed.
This GL FBO Unity bug was tracked by LaunchPad Bug 987304, "3D apps run much slower under Unity." The sad part is this is not the first time this issue has happened with Unity, but there was this same fix last year, until it ended up being reverted. Last year there was the bug 861061, "All apps have a lower frame rate under Unity." That earlier bug had this same FBO fix but then was reverted from Unity 5.10 since there happened to be a weird Dash bug for some in Unity.
To see how Unity 5.12 now performs when running full-screen OpenGL games, here's some benchmarks comparing Unity 5.10, Unity 2D 5.10, Unity 5.12, and Unity 2D 5.12. The Unity 2D 5.12 update does not have any OpenGL fixes, but these numbers were included for reference anyhow. For those interested in then seeing how the OpenGL performance compares under other desktop environments, there is the Intel Ivy Bridge desktop comparison from the end of May and Tweaking KDE's KWin For Linux Gaming Performance and Ubuntu 12.04 Desktops Impact Performance, Power Consumption and Gaming/Graphics Performance On Unity, GNOME, KDE, Xfce.