Would be cool if you don't only think inside your box. ;)
There are also AMD users out there, so if asking for multi GPU support, please ask for all of us, and not only yourself. Thank you!
BTW: Yes low FPS is also a thing cause of this is still Early Access. Also you don't have a beefy CPU - as i5-CPUs are not the highend stuff they pretend to be (sometimes) ^^
For your information, my Hardware:
I don't have 60FPS often.