Why not buy a Xeon instead of i5 or i7?
Browsing search a bit: the almost Pavlov'ian response to this question is immediately barked as "Xeon for server, Core i7 for gaming". There is an obvious problem with this, because paying for Intel's on-die HD 4000 graphics doesn't make a whole lot of sense for a gaming rig. But review sites don't really do Xeon, you can't find them in the AT Bench tool for instance.
Most motherboards support the socket 1155 Xeon just as well as other Ivy Bridge CPUs(?) and as it turns out you have to not just consult the MB RAM compatibility list, but also check the CPU RAM compatibility list to find suitable memory. With Xeon you have the option to use error correcting memory as well, but you don't have to.
Comparing the i7-3770K to the E3-1270V2, they appear to be exactly the same chip and score exactly alike in benchmarks, the Xeon comes sans integrated Graphics offering a whole bunch of virtualization features instead. Though they may be just as useless to me and you as integrated graphics.
Intel's own comparison:
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