You can stream with this rig anything you want (just because x264 encoder uses the CPU and its really good, one of the best gaming/streaming CPUs right now, only the X99-plattform offers more and also costs way more).
Your download speed doesnt matter, we need upload.
Go to speedtest.net and select a couple of local servers and then a couple of servers in cities where Twitch.TV servers are sitting (like Frankfurt in Germany, London, and some USA locations if you live there and not in EU^^). Then tell us how high your upload speed is. If you got 3mbit/s or higher, you are good to go with 720p 60FPS.
P.S. but remember that your 750Ti is the entry level GPU from Nvidia, so you will most likely meet some low FPS ingame before your CPU runs out of steam. Specially in newer, demanding games, not in Minecraft.