Found right away with OpenArena and other select tests was something odd not seen in earlier testing... The Core i7 4770K "Haswell" processor with HD Graphics 4600 wasn't the fastest tested Linux graphics, but was outperformed by the previous-generation Core i7 3770K "Ivy Bridge" with HD Graphics 4000. Haswell graphics are generally much faster than Ivy Bridge but it looks like some Haswell performance regression may have crept into the open-source Intel Linux driver stack.
With the Prey (id Tech 4) game, the HD Graphics 4600 from the Core i7 3770K was still out running the Core i7 4770K with HD Graphics 4600.
Again, the Intel Linux OpenGL performance right now with Linux 3.13 and Mesa 10.0.1 stable is in a weird shape... Sandy Bridge and Ivy Bridge are much closer (or exceeding) the Haswell performance levels on Ubuntu Linux.