StupidGuy did mentioned that he was running with 2x LDT multi.

That explains the high HTT speed, which enables him to run high speed overclocking.

On nForce3 (DFI 250Gb to be exact) I remember that the system refuse to load with 2x multi, while with 2.5x the overall Hypertransport speed is already exceeding its limit at 320MHz. I don't know with nForce4 S-754 because I have never experienced using it before, but this 6100 chipset is probably the reason of this such high overclocking.

I also want to know the stepping.

was it prime stable more than 8 hours?

I'm running 3x at 338 on my nF3 prime stable for more than 12hours, 2.5x will do fine as well.... but no go with 2x

2x will help better stability

the rule of thumb is to make sure HT speed doesnot exceed 800mhz, but slightly more wont hurt

Theoretically.... if both had the same RAM speed and timing, there will be no difference at all. This is because K8 HTT does not work the same way as conventional FSB. No matter what divider you use including 1:1 ... the CPU and the memory will always be on divider, so bottleneck issue is not a concern. Unless you can run the RAM at the same clockspeed as the processor, then it is really a perfect bus efficiency.

So, referring to your options, any will do, but try to use RAM divider which allows higher speed.