I was originally intending to test this with benchmarks but, after a little while, I realized that Ivy Bridge was not supported. This graphics driver starts and ends with Haswell. While I cannot verify their claims, Intel advertises up to 30% more performance in some OpenCL tasks and a 10% increase in games like Batman: Arkham City and Sleeping Dogs. They even claim double performance out of League of Legends at 1366×768.
Intel is giving gamers a "free lunch".
The driver also tunes Conservative Morphological Anti-Aliasing (CMAA). They claim it looks better than MLAA and FXAA, "without performance impact" (their whitepaper from March showed a ~1-to-1.5 millisecond cost on Intel HD 5000). Intel recommends disabling it after exiting games to prevent it from blurring other applications, and they automatically disable it in Windows, Internet Explorer, Chrome, Firefox, and Windows 8.1 Photo.
Adaptive Rendering Control was also added in this driver. This limits redrawing identical frames by comparing the ones it does draw with previously drawn ones, and adjusts the frame rate accordingly. This is most useful for games like Angry Birds, Minesweeper, and Bejeweled LIVE. It is disabled when not on battery power, or when the driver is set to "Maximum Performance".