I want to use 2 GTX 650 ti boost sli graphics cards. I have a Z77X-UD5H motherboard and i5 2500k processor, 650w power supply and 16gb memory and have got a choice 1 pci express x 16 or 2 pci express x8 or 2 pci express x4 + 1 pci express x8 and have a case big enough but I would like to know if using the 2 of this graphics card is good for the latest games. I am using windows 7 . I can only afford £200 - £250 ish.