how about compatability dual CPU server board (e.g. INTEL S5500BC Bluff Creek) and desktop processor i7-920 (http://ark.intel.com/Product.aspx?id=37147)?
Same socket but official compatability is only Xeon CPU (it is strange for me)
Thanks a lot, I need build low cost server and this could be the right way
Check http://www.intel.com/support/motherboards/server/sb/CS-030213.htm for supported processors.
Anything you try, that hasn't been tested, will give unpredictable results at best. At worst, you may permanently damage both processor and motherboard.