I have two sticks of DDR3 G.Skill 1600 7-8-7-24 1.6 installed into a Gigabyte GA-770T-USB3 Mobo. By default i had to change the ram down to 7/87/7/24 it defaulted at 8/9/9/24. If i turn on manual in the BIOS next to the ram times it say SPD and AUTO, now from what little i understand so far SPD is basically what the ram tells the bios it can run at, but truthfully i have no clue. If i set the speeds to the SPD they will be considerally better. Should I? Keep in mind that the ram timings 7/8/7/24 were changed to that by me because that's the manufacturers rating. I wanna get the most of my machine I am a hard core gamer and just learning of Overclocking. But i don't even know if this counts!
Change them to the SPD settings and then run memtest overnight to check for stability. They should run at the manufacture's recommended speed but it's not always so simple. The memory controller is on your CPU and some are finickier than others (can vary by how many DIMMS are populated and size of RAM).
Also, those ratings may be for an Intel system, AMD may need slightly different timings or voltages.