Corsair 2x1Gb PC2-8500 + Asus P5W64-WS Expert help needed please.

Hi, I wonder if anyone can help me.

Recently I built a new system, stock speeds and unclocked, for now. All is fine except I can't get the RAM I bought working as intended.

CPU : Conroe E6600 @2.40Ghz

RAM : Corsair XMS2 2x1gb of PC2-8500C5
http://www.corsair.com/corsair/products/specs/TWIN2X2048-8500C5.pdf

MOTHERBOARD : ASUS P5W64WS "Wall Street Quartet" Rev 1.01G, Latest Bios (0304)http://usa.asus.com/products4.aspx?l1=3&l2=11&l3=248&model=1341&modelmenu=1

I have installed it and set on dual channel interleave, I have used dimm 1 and dimm 3 slots.

Corsair say that it is fine on 1066Mhz/8500 5-5-5-15 @ 2.2v.
Well I can't get it to work at that speed. I can get it to DDR2-800Mhz no problem, with the mobo showing it as pc6400 when I boot up.

How can I get it to 1066Mhz/8500 please ?

The mobo has an option for it, but I was just wondering about something I heard saying that you need to increase the FSB to achieve this ? Is this correct ? I have tried using SPD settings and all various other manual
ones but can't get 1066Mhz/8500 5-5-5-15 @ 2.2v which it is guaranteed to do.

Please help me out here and explain, I really would appreciate it.

Thank you for your time in advance.

In the bios there is a setting to set RAM speeds, all the way up to speeds like DDR1600, but 1066 is in there as long as the FSB is set to 266 or on auto. This is going to have to be achieved by a divider, as is the memory will not run 1:1 with the FSB unless you can achieve a FSB of 533MHz, and I don't think any 975x MB can do so un-modded.

To get to this point, from the main bios page, you have to arrow over right a few times to Advanced>Asus AI Overclock>MAnual.

Intel FSB are quad pumped. Meaning the base FSB is 266. For reach the effective FSB: 266 * 4 = 1066FSB.
Now memory speeds run 1:1 with the fSB in a sense that if you set the FSB to 533mhz (which BTW is hellova overclock, and will most likely need extreme cooling to reach), only then will your 1066 DDR2 run 1:1.

Thanks for the response, I may have been a little unclear about the BIOS manual configuration. I had already gone into that and changed it manually to achieve 6400 (800 Mhz) but when I changed it to 8500 (1066Mhz), that's when it wouldn't boot into windows. I did adjust the voltage to 2.20v as stated by Corsair and set the 5-5-5-15 timings.

I have read your post and it seems that even though :

Mobo is capable of 1066Mhz (Asus P5W64WS)
Memory is capable of 1066Mhz
CPU appears to be 1066Mhz (E6600 Conroe), even intel state 1066Mhz FSB for that chip.

You are saying that the real FSB speed of the E6600 is 266Mhz(x4) and therefore the aforementioned memory will only run as high as pc6400/800Mhz unless the cpu is clocked to achieve a 533Mhz real FSB ? Only then will the memory modules run at 8500/1066Mhz ?

Naughty Corsair