Overclocking Q9550 help

titaniumx3

titaniumx3

titaniumx3

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11 May 2006
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My relevant specs are as follows:

Q9550 (Rev E0)
Asus P5Q Pro (Latest BIOS - 2102)
2x2gb OCZ DDR2-800
Windows 7 64bit & Windows XP 32bit (Tested overclocks in Win 7 only)

The Q9550 has been perfectly stable at 3.4ghz since I got it last year:

cpuzcpu.jpg
cpuzmem.jpg


Everything in AI Tweaker is at auto, except FSB@400, DRAM timings manually set at 5-4-4-15 and CPU voltage set as 1.275. As I said, everything is perfectly stable like this but as soon as I try to increase FSB any higher I start getting errors in Prime95 and Intel Burn Test.

I then fiddled with several settings in AI Tweaker and got varied results, pretty much immediately get errors in IBT. Sometimes I can't even get to run Prime95/IBT, because either explorer crashes or I get BSOD.

So then I decided to set absolutely everything to auto and just increase FSB. I managed to boot into Windows 7 @ 3.8ghz (450x8.5) and magically I get no calculation errors in IBT or Prime95 .... but for some reason either program will randomly crash. I thought this was strange because I could go through 20 runs of IBT and get no calc errors, but if I try it again I suddenly get a crash (i.e. windows says it has stopped responding). At 3.8ghz, the bios automatically sets cpu voltage at 1.34 (according to CPU-Z) and when running IBT, temps don't go above 68C.

I'm not sure whats causing it, but I manually set DRAM timings to 5-4-4-15 (at Auto they're higher, 6-6- something) and could barely use Windows since explorer and catalyst control centre kept crashing.

I got a feeling it's the RAM thats limiting the overclock, but then again it could be the Northbridge. I do think the CPU is capable of more though.


Any ideas? Would getting faster ram (say DDR2-1066) help?
 
The memory is rated for 400mhz, but it'll probably do 420-440mhz at default volts/timings. However, as soon as you push past 450mhz bus speed, it's not going to like it. I don't believe you have a divider/ratio that takes the memory back to 800mhz or thereabouts, its all uphill from here..

PC8500 RAM would remove this limit, as its rated for 1066mhz.

I have the exact same setup (bios revision and CPU stepping) apart from i have 8gb of Kingston HyperX 1066mhz stuff, and i realised this limitation of PC6400 RAM when i was overclocking.

Also, slightly off topic, but what are your CPU PPL, FSB Termination and Northbridge values set to? The first two are overvolted on this board. Set your CPU PPL to 1.52v (two notches up from auto), and FSB Term to 1.14v (again, two notches above auto). For the northbridge, manually set this to 1.20v, as otherwise you'll have no idea what it is defaulting to on auto. This is a good starting point to try. You're safe up to 1.4v on the NB, but you shouldn't really ever need to go that high. If the system doesnt POST, try 1.26v. Should be more than adequate for 3.4ghz and 2 sticks of memory. The rest of the settings i leave on auto.
 
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Thanks a lot mate, I have no idea what those three settings are lol, because I left them all at auto. I'll try them settings and report back.

Also, what is your vcore set to? Is 1.34 high for this particular processor?
 
My settings at the moment:

FSB - 377 x 8.5 (3200mhz)
RAM - 502mhz (set yours to 800mhz or below)
PCI-E Freq - 101
Vcore - 1.160 under CPU-Z Load. (think its 1.1750 in BIOS)
CPU PPL - 1.52v
FSB Term - 1.14v
NB - 1.24v
SB - Auto
Load Line Calibration - Enabled
Spread Spectrum (for both) - Disabled
Last setting on the bottom - Set to performance mode instead of optimized.

Disable C1E and Speedstep functions on the other tab.

The options in bold are pretty important, and defiantly have a bearing on how stable an overclock is.

To answer your question, no not really. 1.368v is the safe limit set by Intel. Anything after this is supposed to degrade the lifespan of the CPU more rapidly, but i've ran mine at 1.40v for a time and it was fine (temps were silly though) Stick with Intel's recommendation and you'll be fine. :)
 
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