@ Ibanfi2: Hm, I think the 13 MHz steps are for Max Boos onlyt - for Baseclock and for Boost you can set variable clocks - at least with GK104 as far as I can tell.
Well, I'm going to set your final settings based on SSD Freak's BIOS. :)
(Gigabyte GTX 660 OC - 1134-1202-1202 MHz GPU, 1650 MHz...