So I am going to be ordering a 480W power supply and a HD 7770 for a computer I bought about 2 years ago (i3-2100, 6gb of ram, 64bit Home Premium. etc.) So I was wondering if there will be an issue using a PCI-Express 3.0 card in a PCI- Express 2.0 slot. I've read online that it should work fine, but I"m not 100% sure. Thanks in advance.