Hi folks. I have a Gigabyte ga-x58-ud3r sli MB and I currently have 3 sticks of Super Talent 2 gb 1600 mhz RAM. I'd like to upgrade this to 4 16 GB sticks of 2000+ mhz RAM. The problem is that the only DDR3 RAM I can find 2000+ comes in 3 x 4 of 2 GB sticks. I can find lower frequency RAM in 4 x 4 sticks. I was wondering why this is. My boards has 4 slots. Also, with it being DDR3, is there any reason I'd want to only use 3 of my slots instead of all 4? Thanks for any clarification.