Crucial Crucial 6GB DDR3 1333 with GA-X58A-UD3R

^ so finally we're checking.

The simplest is to adjust your Memory Multiplier to 12 {Speed / BCLK}. However, if your Rated speed is exceeded by ~ +15-20% you will begin to have errors/BSOD/instability. 1333 MHz + 20% (~ 267 MHz) is that threshold.

Initially, I would try the stock CAS speeds, increase the Memory multiplier, and increase by +0.2 Volts. Next I would increase the BCLK from 133 to 160 and decrease the MM to 10, but still keep the CAS and increase by +0.2 Volts. Messing around with CAS can do more harm than good. BTW if you DDR has a poor heat spreader even if you can find a stable setting Prime95 may overheat the RAM -> unstable, and lets not forget Memtest86+.

Good Luck!

saint19 knows his RAM.

I know this RAM:
CT3KIT25664BA1339

* Module Size: 6GB kit (2GBx3)
* Package: 240-pin DIMM
* Feature: DDR3 PC3-10600
* Specs: DDR3 PC3-10600 • CL=9 • Unbuffered • NON-ECC • DDR3-1333 • 1.5V • 256Meg x 64 •

Features
Compatible with Asus P6T WS Pro

^Again, since "OC RAM" is the topic at hand - KEEP the rated CAS and/or lower. The best & most stable performance improvements are via BCLK, and lastly increase the Voltage ONLY if needed. Anyone who knows RAM & RAM OC knows this off the top of their head w/o thinking. You will be tinkering with both CPU & RAM OC, and in my experience I first find a 100% stable CPU OC with RAM @ baseline {rated speeds/CAS/Voltage} and -> then tweak the RAM

In addition, to {check} the RAM OC isolate the CPU speed by beeping it the SAME {e.g. 133 X 20 = 2.66 GHz ; 160 X 17 = 2.72 GHz}, and run Super PI.
Info - http://en.wikipedia.org/wiki/Super_PI
D/L - http://virgilioborges.com.br/hyperpi/

Good Luck!

Footnote - if you follow my advice you "may" be able to get 25~30% RAM OC. I've found 1333 ~ 20% and 1600 ~ 25% increases are "ideal." Heat is the enemy and poor/ineffective heat spreaders keep the "stable" RAM OC down.

edit:
CT3KIT25664BA1339 9-9-9-24 @ 1.5V -> Keep those settings; since this DDR has NO heat sinks don't expect more than 1500-1600 MHz <or> aim a fan over the tops of the sticks.

^ First recommended both CAS + Voltage - but now lower - make up your mind?! I know I'm not clairvoyant.

@jaquith -> "KEEP the rated CAS and/or lower" & "lastly increase the Voltage ONLY if needed"

Voltage + Speed = Heat...no heatsinks...~+20%...going to get hot + unstable. The OP RAM isn't really a "good candidate" for OC, but I 100% confident that it can be OC - the "Question is how much?"

edit: OP needs a baseline first. Raising or lowering CAS need to b done last changes may increase or decrease performance.

Yeah?! It isn't stable @ 1600 MHz with CAS + Volatges used.

And the "Idea" is to leave alone BOTH CAS + Voltages to get a baseline with the "Memory Multiplier to 12" as I posted 1st. Then "IF" needed mess around with the Voltages and "IF" you raise the CAS then you defeat the RAM OC.