Overclocking Memory/CPU AMD 960T BE 6 unlocked

AMD 960t BE 6 Unlocked
Gigabyte 970a-UD3 Mobo
Gskill Ripjaw DDR3-1600 4gbx2 9-9-9-24 stock
Coolermaster Hyper 212 plus PSU
Raidmax RS 530SS heatsink
Radeon XFX 6770 GPU

CPU: x16 4000MHz
CPU NB: x12 3000MHz
Core Performance Boost: Disabled
CPU Host Clock Control: Manual
CPU Frequency: 250
HT Link Frequency: x9 2250MHz
Memory Clock: 5.33 1332 mhz Dram voltage 1.51v

Voltages
CPU NB vid control 1.3v
Cpu voltage control 1.475

Hello all. I am trying to get my system dialed in and have had some really great help from a few people. I am very new to overclocking and this is the first system I have built. I am sadly already addicted to this drug.

Anyway, I am thinking that my CPU is overclocked correctly and seems to be stable in the games I play. but I think there is a problem with the RAM settings. my ram is rated for 1600 but if I go over the 5.33 to the 6.66 setting to get my memory to 1666 I cant pass the memtest, and games will crash. I dont know if this is a voltage issue or if I just cant fully use the memory. If I back it down to 1332 it will pass memtest and games dont crash. I would also like to adjust the timings, however I think I need to get this solved before I can move on.

If anyone has some advice or needs more info and would be willing to throw some advice my way I would be very grateful. I am reading Dolk's guide but the memory section is like trying to read arabic.

I would like to overclock this or at least get the max I can out of it, just not sure where I should go from here. Thanks in advance for any advice.

I am mainly using this for gaming. I set the RAM timings manually (which I hadnt done prior) and that let me pass memtest86 at 1666. I dont know if it will continue to be stable in games but I am crossing my fingers. I upped the voltage slightly as well, not much but a little. I am still struggling to understand prime95. I get worker stopped on some of the tests, but have to do some research to see what it all means. as far as unlocking the other 2 cores, perhaps that does make it unstable. I have to spend a weekend tinkering with that back and forth. If anyone knows of a good Prime95 guide I would be interested to read it. I will feel alot more comfortable if it can pass that for a few hours.