It's really important that you take it one step at a time. There are three major factors: how fast the cpu will run; how fast the hyperlink transport will run; and how fast the ram will run. We can take the second one right out: most hyperlink tunnels won't run much over their rated speed, or at least not without further tweaking for little benefit.
So first step should be to decide which of these to try first. If you want to ramp up the CPU and find its limits, set the memory divider low to make sure the ram stays under spec, and set the HT multiplier low to keep the hypertransport under spec. Now fiddle with the base clock, cpu multiplier, and vCore until you have the highest stable speed for the CPU.
At this point you can either accept things as they are, and set the ram multiplier so that at the new base clock freq. the ram runs under spec. (i.e. 230 mhz base clock * 4/5, which is roughly the 166 mhz ram divider), as well as keeping the HT multiplier set to 4x (4 x 230 = 920 mhz.)
Alternatively, you can now slow the CPU down and see how fast the ram will run. Do this by setting the CPU multiplier back. If you had 230 x 11, for example, set it to 230 x 8. Now the CPU will run at 1840 mhz, and won't cause any problems. You can then try different ram dividers until you see how fast the ram can run without causing errors. Bear in mind that a system will often boot fine with the ram o/c'd, but will show memory errors when the whole range is tested. Proceed from the assumption that the system should never cause an error, ever. So you are looking for a combination of ram speed and cpu clock that will run at high loads for a very long time without error.
Have fun

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