1600 MHz DDR3 running at 800 MHz / 1N vs. 2N?

[Ungerbluzen]

Model of the motherboard: ASRock Fatal1ty P67 PROFESSIONAL (B3)
Model of the memory: G.SKILL F3-12800CL7D-8GBXH
Model of the CPU: Intel Core i5-2500

Both Speccy and CPU-Z report that the RAM is running at 800 Mhz. I fiddled with the BIOS, but nothing makes any difference to that. I want to see 1600. I have the feeling that this is noobism of the worst kind, but I'm at a loss.

Also, I just yesterday realized that I was running the BIOS default 11-11-11-28(?) and went in and set XMP, which set it to the advertised 7-8-7-24, but it defaults to 1N when the sticks are 2N. Should I do something about that? (The tighter timings actually improved performance noticeably in Crysis and Warhead.)

Thanks.

[Tradesman]

Tighter timings are much better, if it will run 1T, that's better than 2T and CPU-Z/Speccy are reflecting the 'true' freq of 800, but this is DDR (DOUBLE Data Rate) so effective is 1600