I also have this question.
I was looking to get a Xeon E3-1230 CPU and use it with a GA-Z68M-D2H motherboard.
As Gloup_Gloup points out Intel states Xeon E3's are compatible with Z68 chipset and ASUS are saying the E3's are supported on their Z68's.
The main thing about Xeons is the ability to use ECC memory, but Non-ECC is also supported. Has Gigabyte just forgotten to put the E3's on the Z68 mobo's compatibility list or is there a specific reason E3's are NOT compatible?
Unfortunately I need to build my system asap and as this question was asked on Jan-4 and has got no answer I'm guessing no-one knows :-(
If anyone at Gigabyte can give a definative answer quickly I'd me most apreciative as I dont particularly want to go Asus.....