The XEON CPU's which come with IGP's are the low end CPU's (E3 only) which are re-branded low to mid range desktop processors that were cherry picked to go through XEON's QC process.

Intel doesn't ship high end desktop or server CPU's with IGP's atm, the decision for the XEON's was to provide video transcoding performance, even highest performance Iris chip is still no match for even a mid range GPU from 5 years ago.