It's expected to work. I've tested it on mine, Haswell i7's own iGPU, and a full sized GCN Radeon, with a game rendering on the Radeon but displaying on the iGP

It's expected to work. I've tested it on mine, Haswell i7's own iGPU, and a full sized GCN Radeon, with a game rendering on the Radeon but displaying on the iGPU. Multi-monitor setup with 2 on the Radeon (normally all 3) and 1 on the iGPU, seemed to work fine. No real visible lag either, from what I could tell with limited testing.