Im not really sure which one I should get or if there is much of a difference between the two. Im particularly confused by where it says "Only qualified 1.5V XMP RAM on Intel Core i3/i5/i7"
Is 1.5v ram more desirable ? Im guessing that this has to do with OC your ram?
Also could someone tell me the working difference between 3 thee type of ram? Am I correct in assuming that 3.) is low profile to conserve space inside smaller cases? or for placing large CPU fans? and the Mhz difference of 1600 and 1866 is a speed boost? If I want increased performance I should go with 1866?
I would go for the lower priced 1600 corsair; the higher you go for the ram speed, the slower the timings. It's a question of how high you intend to overclock and how much you're willing to spend. Most of those ram speeds won't hold without a small voltage increase. That's why 1.5v is preferable, so you can increase the voltage to 1.65 when overclocking and remain within Intel's recommended spec of 1.65. I usually lower my ram speed a little before cranking up the cpu speed so it evens out at the recommended speed. Order your ram today before the 15% discount is gone, and get the exact quantity you want so all the ram sticks match. If you want 16 gb, get four sticks now. 8 gb is normally enough unless you're doing alot of video work. I'm running my ram slower now at 1066 until foxconn sends me a replacement bios; when I increase my ram speed manually, this old 790gx board increases the voltage to 1.8, which I feel is too high for any ddr3. But at 1066, my 1600 ram is running at faster timings of 7-7-7-20 so the speed feels the same. I can't tell the difference between 1066 and 1600 due to the faster timings.
Thank you for that detailed response, When you say the speeds won't hold, do you mean during OC? if the timings get slower the fast you go, why is faster more expensive? sounds like its having the opposite of the desired effect? or do you buy slower simply for more safety space when Overclocking?
Frankly, some of the high end ram won't even run at the guaranteed timings with certain motherboards unless the voltage is just right. I just don't feel it's worth the extra cost. That's just my opinion. You may have good luck getting it to run at the faster timings with your board, but overclocking may still require you to drop the ram fsb first before increasing the cpu fsb for better stability.