Attempting to OCing Q9550 @ 3.6ghz on ASUS P5N-D

[GeneralDodo]

So I built a new PC recently, and decided that I wanted to overclock it.. it's a Q9550 on an ASUS P5N-D Motherboard, and I have 4x Corsair Dominator CM2X1024-8500C5D modules installed.. I've read that more RAM sticks can cause stability issues, but of course i'd like to use it all.

At any rate, i've read numerous guides on overclocking, i'm not exactly new to it but at times have trouble understanding why i'm getting instability.

I just can't seem to be able to get my Q9550 running at 3.6ghz stable on this board. At one point, I was able to boot up into Vista successfully, and be able to run IntelBurnTest which failed on the fifth pass. After a few more times of tweaking the settings and restarting, I would just crash as soon as I logged into Vista.

As of right now, the settings i've tried for 3.6ghz has been the following:

425 x8.5
running memory @ 1:1

vCore @ 1.2750
RAM @ 2.050 ( AI Suite will read 2.1 )
HT @ 1.36
NB @ 1.46
SB @ 1.50

These are all the voltage options the P5N-D provides btw.. :x

I've read that HT above 1.36 isn't exactly safe.. and 1.40 for NB either, but decided to give it a shot and it actually helped to raise it above 1.40.

RAM Timings @ 5-5-5-15-2t

This is what i've used to successfully boot into Vista at 3.6ghz, but it runs unstable and sometimes won't even make it as far as the Vista log in as previously stated. IntelBurnTest and Prime95 Small FFT's seem to do well (somewhat), Blend Tests and In-place Large FFT's fail. I really do think that perhaps my memory is causing the instability, but I am not sure what I can do to make it any more stable. I've tried messing with the timings to no avail. Some help or a point in the right direction would be greatly appreciated

[Mussels]

with all banks of memory in use, you're going to need to raise the NB volts more than you would without. Since you're rasing the FSB high as well - yeah, you're gunna need more and more NB voltage.

Since you have an Nvidia 750i, you may not get great overclocks. Nv chipsets arent good for high FSB clocks compared to the intel chipsets.

[gaximodo]

750I's are good at ocing duo's not quad's. But 420~ish FSB for quads is possible for them.
you don't really need that much volts for HT to help oc the cpu.
probably rise the vcore a little bit more might help.(try to adjust GTLREF for each core could help too)

[GeneralDodo]

One question I can't seem to find an exact answer on is how high is too high or what is the max safe limit for NB voltage? I keep seeing people post up different answers for that they deem to be a 'safe' voltage.

As for setting the GTLREF for each core.. yea, I would if this board's BIOS had the option to do so.. seems really limited in what I can do in terms of setting voltage.

[gaximodo]

1.45~ish is fine for NV NB,
never tried go above 1.5 so i don't know if its safe or not.
(using EVGA 750I FTW)

[GeneralDodo]

I tried raising the NB up to 1.48 but no go, still makes my computer restart after logging into Vista which has been the issue i've been facing for a while now trying to get to 3.6ghz. I really think it has to do with my ram's timings.. how can I ensure that my ram timings won't crash me? I'm not entirely sure on how to get timings that I guess you could say would be "crash proof" lol

Btw, I do run my Q9550 @ 3.4 stable on 5-5-5-15-2t

RAM @ 2.1
vCore @ 1.248
NB @ 1.36
HTT @ 1.36