Hi. I've managed to push my Q6600 to nearly 3.7 Ghz and my  4x1 Gb Crucial Ballistics DDR2 Ram PC 6400 800 Mhz,  to 1105 Mhz with 5-5-5-15 settings.

Still the Sim is not performing well IMO -  with sliders at 3/4 approx.

Does anybody know if this RAM performs better at a lower speed, say 960 Mhz, and then be able to have the timing set to 4-4-4-12 instead..?

I can't really see any difference myself, but if anybody here are familiar with this combo, I would like an opinion.

Thanks for any help on this...

The "sweet spot" theory is true. After a certain point, it isn't reliable anymore. If you adjust the latencies a little higher to get more speed, it really defeats the pourpose. It runs at 1000+ MHz, true, but if it waits 5 clock cycles rather than 4 to charge and strobe, the MHz seems to not matter anymore. With RAM, I use the lowest latencies possible, then try to push the MHz a little. I'm no tech MASTER, but I have noticed this to be true. Once you're at 4-4-4-12, that's about as rapid as ddr2 can strobe, charge, whatever. There is an inverse correlation to latency and speed. That's all I know about it. If you can get a higher score on a benchmarking tool, ok, but what we really want is for it to run programs and games faster. 4-4-4-12 is as tight as it gets.
Keep pushin! Hope this helps...