Phoronix reports that Intel has published the open-source Linux GPU kernel driver for the next-gen Broadwell chips and that the graphics improvements should be significant. From the article:
The changes are massive and it’s looking like the Broadwell graphics improvements will be astonishing and provide significant improvements over Haswell and earlier generations of Intel graphics.
Code comments from Intel indicate that these processors shipping in 2014 will have “some of the biggest changes we’ve seen on the execution and memory management side of the GPU” and “dwarf any other silicon iteration during my tenure, and certainly can compete with the likes of the gen3->gen4 changes.”
The driver support should begin appearing in the next round of Linux distributions.