Last September, I upgraded to a late 2013 model rMBP (Core i5 2.4ghz with Intel Iris 5100). It has largely been fantastic for gaming in Windows 7 — I've played through Bioshock Infinite, Dishonored, Dark Souls and others all without many problems and with a good performance and quality.
However, some games give me a really odd glitch when certain settings are enabled. Spec Ops: The Line, The Vanishing of Ethan Carter, and Borderlands 2 (so far) have all displayed odd red lines/artifacting, and though I can sometimes remove them by fiddling with settings, I was hoping someone would know if there is any root cause of this. I updated to the latest drivers this morning while trying to fix this, and there was no change.
Screenshot of the glitch in Borderlands, where the glitch is apparently tied to the Depth of Field setting: