Also agree about Gamer HD, that was mainly just a coordinated thing with Xsplit.
There is also the option of GPU assisted encoding through OpenCL. There are a few encoders with look ahead available for that already out, but I don't know how to turn them into a .dll for OBS. That's been ongoing for awhile on doom9 as well as other websites.
AMD and Nvidia also have their own versions of Quicksync, so even if you don't have a iGPU you could still purchase one of those cards and use it for that. OpenCL works with all three vendors.