i just went to try to oc my e6600, and i'm using 2 pair of corsair xms2 pc800 5-5-5-12

anyway i notice that, i can't go further like 7x450(sometimes 3dmark06 will have error, worst is the pc restart), 6x500. however i can manage to run until 7x445 or 8x390 or 9x333. so, it's my cpu limitation or my ram? i had tried to raise up cpu vcore to 1.3371 to see whether it get stable on 7x450 but it doesn't help. and also +0.1 +0.2 for dram voltage.

by using sisoftware sandra lite XI,(memory bandwidth test and memory latency test) it show better result on 7x445, which timing is 5-6-6-21. as compare to 8x390, 5-5-5-18 or 9x333 timing 5-5-5-15. i though normally the smaller the timing = faster ... so..can anyone explain to me? thanks in advance.

edited from previous..can someone tell me..? very appreciate it..

specs?

Intel c2d E660
Gigabyte P35-DS3
2 pair [corsair xms2 pc800 5-5-5-12 2GB]
Gigabyte 8800gts 320mb
wd 160gb hdd
enlight psu 530w

check your RAM voltage requirements, is it 2v or 2.1v or less than 2v? When you get the RAM voltage, set it in BIOS. For example RAM need 2v for normal operation, BIOS RAM voltage are begin with 1.8v, so you need to set +0.2v.

Check you RAM divider in BIOS, try to make RAM speed are less than it specs when you overclock CPU. For ex. you set FSB 333, RAM will be at 1000 or 667 according divider, set it at 667, but later you can set it to 1000 when you are finish OCing CPU (if your RAM can handle 1000).

Higher FSB and tighter timings will give more performance, but carefull for stability if your RAM can't handle it. Do a higher FSB but loosen the timings for your RAM.

I don't know if P35 has a FSB voltage and NB voltage, check it and raise it a little to give stability. Check your NB temp after doing this, put a fan if necessary.

ok. i will try it. thanks for the info.

i had just google my corsair ram, they were using promos chipset. is the promos can be oc well? how further can it go?

p/s: i changed the ram ratio to manual..which is x2, ..means if i set my fsb to 400, then it is running at 800mhz.
p/s2: i had raise the FSB voltage,(G)MCH voltage but seem not helping.

ddr2 overvoltage control
pci-e overvoltage control
FSB overvoltage control
(G)MCH overvoltage control
cpu voltage control
p/s:3 seem dun have NB voltage..

FSB and g(MCH) voltage are helping the CPU stability while overclocking.

Set the PCI-E freq at 100 and leave at normal for PCI-e voltage.

DDR2 overvoltage ranging from +0.1 - +0.5 v (could be more), if your RAM specs are at 800Mhz 2.1v, then set +0.3v at DDR2 overvoltage.

ps: NB = g(MCH)
ps2: don't really know about promos chipset.

hmm..but i found the official web state that they used 1.9v to get 5-5-5-12 .. should i go more than 1.9v? and..what is pci-e freq? not really know abt it

If it's official voltage then set it at 1.9v and the timings too. You can try to make it more tight at 4-4-4-15 and give 2.0 or 2.1v. Test it with Memtest though to know RAM stability.

PCI-e freq is the frequency given to PCI-Express slot means to your GPU. You don't need to change the value, better leave it at 100 because 100MHz already give wide bandwidth for your GPU to operate.

i see.. ok i will try it later. thank you.

I would check what the standard bio setting is. I believe its 1.8 So to get it to the correct voltage, you have up it .1 and with any oc, you may have to move it to +.2 or +.3

Also, change the ram ratio to 1:1
Manually set the memory timings to 5-5-5-15.

That should give you room to OC. Once you get a stable OC, you can start tweaking things, like lowering your timings etc.

My ram was very picky in the oc of my rig. I can push my cpu to 3.5, but the memory keeps on crapping out and I had to retard my timings horribly. What I have now seems to be a sweet spot for my ram.

my bios can't set the memory timing.. where can i get the software to config it manually?

btw i tried 1.4 vcore and +0.4v for the ram (2.2v), no luck..also can't run stable on 450x7. *i'm using 1:1 ratio.

it's my cpu limitation?

You have to go into M.I.T. hidden feature by pressing ctrl-F1 when you are in BIOS main menu.
Have you read the mainboard manual, btw ?

i did read it but din find any info about ctrl-F1? or i miss it? :x

I have Corsair XMS2 DDR2 6400 C4 4GB. I currently have my processor 10% overclocked and reduced the memory frequency. Rated frequency is 800MHz and right now it is at 750MHz. If I bump it back up, what do you think is a maximum stable frequency above 800MHz? Will 900MHz be too much?

The XMS2s are pretty nice. I have the DDR2 PC6400 one gig sticks, 5-5-5-12, 1.9v. I've gotten them to 510 mhz (1020) with 2.1 volts. Of course at looser timings. I'm not saying they've all got good overclocking potential but they've done me well.

Try it out with "auto" memory timings. Once stable you can try tightening them up.

So your memory clock is 1020 MHz (with SPD being 800 MHz) correct?

Yes, I wanted to see how far they would go on my Gigabyte board. I don't know if I reached the rams' limits or my motherboard's FSB. I've settled at 930 for now.

I ran it at 1020 overnight for about 8 hours on Orthos and Sandra and it was stable. I can't recall the timings. It was on auto though, so we're talking some high numbers.

Ok...thanks. It looks I'll try to set mine for around 900MHz. I have the C4 with 4-4-4-12 timing. I set that already but was afraid about going above the 800 MHz.