All you alternative OS types out there aren't going to be happy with this article.

As this Windows 7 vs. Ubuntu 12.04 graphics comparison for Intel Sandy/Ivy Bridge hardware was getting underway, I certainly did not expect to see the Intel Linux graphics driver be slaughtered so badly. It was just last year that for Sandy Bridge the Linux driver was able to outpace the Windows OpenGL driver for several OpenGL workloads. Since then, the Intel OTC developers have been aggressive to round out the Sandy Bridge feature-set, get rolling early on Ivy Bridge support so that there's effective "out of the box" support at launch (they were successful with the stock Ubuntu 12.04 / Fedora 17 software packages supporting Ivy Bridge hardware), and catching up with OpenGL compliance and other areas. However, the Windows developers at Intel have also evidently been quite aggressive in their work too over the past year.

The only cross-platform game where there was similar performance between Windows 7 and Ubuntu 12.04 for Intel HD 3000/4000 graphics was with Nexuiz. With the other tested OpenGL games/benchmarks, the Windows 7 driver led to frame-rates that were commonly 50~80% higher than what was provided by the open-source Intel Linux driver.

Beyond the Intel Windows driver being faster, it has better OpenGL support too. The Intel Linux developers working on Mesa are still battling for OpenGL 3.1 feature compliance, which they hope to have ready this summer for the Mesa 8.1 release. The open-source Intel Linux driver also still is not able to ship with support by default for S3TC texture compression or floating-point textures due to patent fears. The Intel Linux graphics driver stack at this point also has no support for OpenCL with Ivy Bridge, among other missing features and functionality.