1666(OC)/1333 how to accomplish

[HedBang]

I have 2-2 <edited> meg sticks of GSkill DDR3 1600 RAM http://www.newegg.com/Product/Produc...82E16820231193

And GIGABYTE GA-MA770T-UD3P AM3 AMD 770 http://www.newegg.com/Product/Produc...82E16813128392

The mobo is listed as supporting DDR3 1666(OC)/1333/1066 and the above RAM is listed on Gigabyte's website.

I'm guessing there are simple answers to this but I have no experience tinkering with memory.

What exactly does it mean when a mobo is stated as supporting 1666(OC)? Is there more to OC'ing the RAM than upping the frequency in BIOS? In BIOS, I've manually changed the Mem clock to x8, so I guess technically running at 1600. (?) Memtest and Prime95 run fine when I leave things at 1333 (default on the board), but crash quite quickly when I up to 1600. The sticks are rated at 1.5 v; the minimum the board goes is 1.6 v. I've upped slightly to 1.62 with no improvement in the stress tests. I've adjusted the timings from 9-9-9-24 to 10-10-10-26 (no improvement), but I don't know what I'm doing when it comes to that.

Am I on the right path playing with voltage and settings? Any suggestions?
I've left the CPU mulitplier at 14, temps never read above 36 deg C.

Thanks

 

[railman]

Did you mean 2 - 2GB sticks of ram? I would drop the voltage back to 1.6 and try timings of 10-10-10-28. If you can change the command rate usually set at 1N or 1T set it to 2N or 2T. you might also try increasing the tRFC dram cycles a step or two and sometimes it is necessary to disable DRAM static read and write when overclocking. A bump in North Bridge voltage may also help.