The Ivy Bridge, Haswell, etc Core-branded CPUs have an on-chip GPU, even if your computer has a external discrete GPU: Xeon does not have an on-chip GPU - thus no Quick Sync - apparently because it was viewed a poor use of on-chip resources for the server and high-end workstation market segment. That doesn't mean it's a GPU task per se, rather the on-chip GPU is where the Quick Sync functional elements were architecturally located. Quick Sync is apparently implemented in the on-chip GPU. At least, not via this route: it's possible H.264 encode will be implemented on the GPUs at some point, which I'd guess would yield comparable results. This implies that the Mac Pro tube won't see comparable encoding speeds to iMac. It's seen as a consumer technology, not a professional one. The issue is that Quick Sync isn't.present in Xeons.
