Whats the fastest (2x4GB) 8gb DDR3 2400 RAM I could get used off ebay? I see many types like Sniper, Hyper X beast, Vengeance pro, etc. Like which ones have the best dies or maybe just best bang for buck? For a Asrock 990FX Fatal1ty Pro /w FX8350. Also how should I go about OCing this setup?