Karenial

Sounds a lot of a bad driver to me, roll back to previous driver version and see if that helps

SL dont eat that much CPU, Ram is what it wants and GPU power, so yeah (i3-i5) 3ghz broadwell is good and should suffice the need for SL (and they overclock rather nicely later on if need more power) Ram: 8gigs is minimum nowadays if you want to run SL, and perhaps surf the internet also same time (SL eats usually 800mb-1gig, Firefox chrome etc... 100mb->, and you want something left for the OS to run on. if going to use Ramdrive or ramdisk for sl cache 8gigs starts to go rather thin GPU if can get hands on cheap used 780 id try that, otherwise it is the main part where you want to place money after RAM (cpu can always be overclocked to be better) Motherboard is pretty much what defines what cpu you will use as for HDD: do you need much space? if not cheapest SSD:s start around 60ish usd with 128gigs of space, should fit OS and SL rather well and give nice smooth run

The Sli part is bit mysterious to be honest, it might work or it wont.. though if running 2 different viewers both assigned to different GPU and screen then you could get some profit out of the SLI part, by assigning one card per viewer

Well looking that you have a i7... would lead to believe you have pci-e 3.0 supporting motherboard, so id go with GTX 970 allows good performance for around 300ish dollars other options are basically GT series also. i dont know of ati cards myself so cant say much of those... but 2gb memory minimum is a good start (also dont expect wonders, i got titan X and get 30fps on ultra... so yeah.. it eats anything you throw at it )