Here's a comparison of the Ubuntu 12.04 LTS versus Microsoft
Windows 7 performance when it comes to using Intel Sandy Bridge and Ivy
Bridge processors with integrated graphics. While the Sandy Bridge
graphics performance was once faster when it came to OpenGL with the
open-source Linux driver, that's no longer the case. The Linux OpenGL
performance for both Sandy Bridge and Ivy Bridge hardware is now slower
in most GL workloads than Intel's Windows 7 x64 driver.