I have a set of 4X4GB Mushkin 2133mhz 1.6v RAM. The motherboard is Gigabyte P55 USB 3.0 and it has xmp1.3 and supports up to 4x4GB 2200 mhz 1.5v. But I am not being able to enable xmp , Is this because of the voltage? What are my options? I want to get the best performance possible. Also my processor is Core i7 860 Lynnfield 2.8ghz.