The 4770K supports some of the common virtualisation features IIRC but the 4820K has a more complete set of those features - I only really use the more basic ones (the odd debian VM for testing stuff) so not sure how big a deal that is.
Just noticed you have the I7 4820, what's the X79-UD3 board you have like Rroff ?
Found a B-grade up for £90 !