ASUS Z9PE D8 WS, BIOS #5004 - supports Ivy Bridge EP QS (confirmed with two Xeon 2697 v2 C0 QEEY QDF)
BIOS #3506 does not work - so make sure to upgrade first before putting the new CPUs in.
The only issue with the CPU right now is that Windows device manager sees bunch of new "Base System Device", "Performance Counters" and "System Interrupt Controller" devices for which no driver is found. I suppose this will be fixed with the Windows update once Ivy Bridge EP is officially out.
Other than that, Windows has no issues with them - all cores are detected and used, and EIST is also working without any issues including turbo frequencies.
Edited by psyq3212 - 7/17/13 at 2:06pm