Am I Missing Something? - or Bad Memory?

[RhoXS]

My E6600 runs 100% stable at 356 X 9 = 3204 GHz and default voltages. Prior to today, I had 2 GB of G.Skill PC2-6400 (DDR2-800) memory installed. I had my AW9D-Max strapped at PSB1066 with a 4:5 ratio to give a 445 MHz DRAM clock. Although overclocked, this G.Skill memory performed perfectly.

Wanting to get some more performance, today I installed 2 GB of G.Skill PC2-8500 (DDR2-1066). I re-strapped to PSB533 with a 2:3 ratio to give a 534 MHz DRAM clock, exactly at the rating of this new memory. With these new settings the machine will not even start up. I experimented with different strap and ratio combinations and the machine will not start with the DRAM clock much above 470 MHz or so. It only starts with the settings in the paragraph above.

Is this new memory bad or am I missing something? I do not believe the "N/B Strap CPU as" setting does anything but change the available ratios. The only parameters that are important are the CPU clock speed and DRAM clock speed. Am I correct? Any better insight into what is limiting my memory speed will be appreciated.

[thideras]

By lowering the NB strab, you are tightening the timings on the NB. That is your problem, put it back to the highest ;)

[RhoXS]

Thanks for the fast response.

The timings, when left in the "SPD" mode, remain the same no matter what strap is selected. They default to 5/5/5/15/35, all but the last number coincides with G.Skill's specification. I did take the first three to the highest 6/6/6 and arbitrarily raised the last two to 20/35 and then 25/50. The machine will still not start up.

I am certainly open to anything else you might suggest. Thanks again.

[thideras]

I said it changes timings on the NB not on the RAM ;)

[RhoXS]

I took your advice (finally). I did not have a good understanding of the NB strap and did not realize it effected the Northbridge timings. I restored the NB strap to PSB1066, a point known to consistently work successfully with a 4:5 ratio (445 MHz DRAM clock). However, leaving the NB strap at 1066, but just changing the ratio to 2:3 (534 MHz DRAM clock), again causes a failure to post. This seems to imply that the NB timings are at a good point but the memory cannot handle a clock exactly at their rated speed.

[meionm]

You could lower multi and raise fsb.