i7 3770

Pretty much explains itself. Do I go with the 730 which is only 1gb and ddr5 or do I go with the 740 which is 2gb and ddr3?

hello, i just bought a new pc and it have 8gb of ram but only 4gb are usable, i checked some threads and said maybe i needed to change the sticks , i checked and changed them and is still the same. I've never had this problem before so i dont know what to do, here are my specs. thanks :)

This is my first ever build and I was wandering if this http://uk.pcpartpicker.com/user/jackoff/saved/4Oc9 is a good build. Thanks in advance for anyone who answers. :)