q9550 overclock problem @4ghz

[Sunburn74]

Hi. I'm having trouble with a newly acquired q9550 processor with E0 stepping. I'm using a ga-ep45-dsq board with 8gb of mushkin 1000mhz ram at 5-5-5-15.

I'm trying to get 4ghz stable (471x8.5). The problem I'm running into is I'm hitting a wall at 2hrs where thread 1 in prime blend fails, but the other 3 keep going for significantly longer. I've bumped the vcore up a smidgeon, but again at exactly 2 hours thread 1 failed in prime95 blend but the other 3 kept going. I'm not exactly sure what to do from here, as my temps aren't super good (63ish under 100 percent load in prime blend using a thermalright 120). Please assist with tips. I'm looking for 24hr stability and am not sure where to go from here.

 

[Bobnova]

When you say exactly two hours, is that to say 2:00:00.00? Or within a minute?
If it's exactly two hours i would start wondering if there is an issue in prime95.
Does it eat it at two hours a couple mhz lower or higher?
I would try another vcore notch, after trying +5/-5mhz, but I'm not as experienced as some around here.

 

[Sunburn74]

literally within 20-30 seconds of each other in terms of time before failure.

I'm currently trying 2 vcore notches above the posted one. if that also fails at 2hrs, i'll start looking at working with the northbridge.

tips wanted though as I only have experience working with dual cores and this is my first quad.

 

[Boulard83]

1.3 is still low. Trying higher can work. Thats nearly the volts i need to run 4.08 or 4.0.

 

[Sunburn74]

So far I've got about 3 hours stable with prime blend but the temps are insane. I know that I have about 2 spots lower I can go on vcore, but can anyone tell me what are reasonable temps for a q9550 at 4ghz? I've got a thermal right ultra and we keep the house generally at about 78 degrees fahrenheit

 

[redduc900]

What are the current values for CPU and MCH Clock Skew? And I assume w/ the current FSB of 472 MHz, the FSB : DRAM ratio is 1:1 (333/667) for an effective 944 MHz effective DRAM freq.? And at the current FSB a vMCH of more than 1.3 - 1.35v shouldn't be needed, even w/ all 4 DIMM slots populated. The Term. Voltage (VTT) of 1.34v is also too high w/ a 45nm quad at a freq. of 472 MHz... try dropping it to 1.2 - 1.25v. Also post a direct link to your RAM, including a pic. w/ Memset open showing all of the current sub-timings.

 

[Sunburn74]

I'll work on getting you the ram timings. I know I'm running the 333mhz strap with a 2.00B multiplier. Its definitely 1:1. I also know the timings are 5-5-5-15.

I opened up mycase and caught something. Apparently a rubber band I was using to hold up the fan on the thermalright had snapped and got caught in the exhaust fan causing it to not blow. I never managed to get the thermalright 120 fan clips to work for me (about2 year ago) and have used rubber bands with fair success to attach fans to them. Occasionally they snap, particularly when I jar my case and they slip to the sharp metal edges of the thermalright I assume. Anyway I'm retesting as we speak.

My cpu and mch clock skew are at default. 900 and 800 ms respectively.

I managed to get a 3 hour run with vmch at 1.3. Will work on dropping it even more though. I did try to drop vtt to 1.20 but only got about 30 mins from each run. I bumped it up to 1.28 (4 degradations) until I decided to go back to what I know is stable and work on other parts a bit more. Personally vtt is a such a stupid setting. I know what it does but how to use it to overclock effectively I've never quite figured out.

 

[redduc900]

Even a VTT of 1.28 is too high at only 472. Try instead adjusting the clock skews and Vref's (CPU, vMCH, and DRAM), tRD (Static tRead Value / PL - Performance Level), etc.

 

[sobe]

Don't know for sure if this will help you but it helped me when getting mine to 4GHz.

http://forums.tweaktown.com/f69/ud3p-q9550-sweet-29409/index2.html

 

[Bobnova]

I knew there was something! Too high a vtt can actually cause instability these days, try turning it down .1v and see how things go, and maybe another .05 past that.

 

[grishenko45]

what speed is the ram at when cpu is at 4ghz???

 

[Sunburn74]

The RAM is 1:1 so I presume its 942mhz. Its rated for 1000mhz.

I'm now getting good stable runs at 4ghz. I attribute it to two things
1) fixing my exhaust fan dropped all temps by at lesat 10 degrees. Now after hours of priming, I'm barely cracking 60 degrees
2) dropping my vmch to 1.3 from 1.4 seems to have added amazing stability. 1.4 was too much and was actually hurting.

My last run was this with great temps:


I'm currently working on dropping the vcore and the vtt as all previous tests with those two where when I had heating issues and the overly high vmch. My vcore lookslike it'll most likely settle at 1.293v input with 1.2v at load, but thats seems pretty nice (considering my old e8400 C0 needed 1.456 to run at 3.91)

 

[qq]

Why don't you turn on load line calibration in BIOS to eliminate CPU vdrop issue?