I do this already, but I have a dedicated streaming PC with a video capture card. Using the -multi switch, I have one streaming at a decent preset to Twitch, 720p, and another at SuperFast preset using a high bitrate, 1080p. The high bitrate makes up for the crappy preset. And my 2600k can handle it, granted it doesn't have to run a game at the same time. So yes, its very possible, even without using Quicksync (I would use Quicksync, but my motherboard is a P67 chipset that doesn't support it).