Windows 7 - Limited on QX9650 Overclock

I've been doing some research lately on overclocking & have not been able to get my QX9650 past 3.33Ghz. My cooling is quite good, as core temps are about 30c at idle & 54c at full load.

My method is very simple for gettting 3.33Ghz. I just increased the multiplier to 10 with most everything else in the BIOS left at default values. I can get it to 3.5Ghz with a 10.5 & it runs fine until I use a program that converts image files. All 4 cores are peaking at 100% during the process, which is normal, but it crashes at 3.5Ghz.

I have 8GB of Kingston Value Ram, which I know isn't useful for OCing the DRAM frequency, so I don't even try it. I've tried underclocking the RAM to see if I can get more out of the CPU, but it doesn't work.

My question is: Is the Kingston Value RAM causing the limitations?

I plan on upgrading to 16GB of RAM soon - with a quad set of G.Skill PC2 6400, which is on the QVL for my board. I'm not buying it merely for OC'ing, but I'm curious if I can push the QX9650 just a little further.

Any recommended settings & ideas are appreciated.

Are you changing the voltage as well?

Yes, I set the CPU voltage to 1.25v. I've read in some articles that the QX9650 will OC to 4Ghz with either no or very little increase in volts, so that should be no issue.

I also read that some QX9650s will overclock more than other QX9650s.

Hi, I am fairly new to O.C myself but I believe I read somewhere that the PSU could be 1 cause if you cant go further because the PSU cant keep enough power going or something like that, download CPU-Z and look at the voltage if it keeps going up and down constantly that could be a sign that your PSU cant keep giving a constant stream of power.

Or it could be your memory, I used to have 3x2 Gig in my system and they was a pain when I tried to overclock, every time I set the RAM to the correct timings from the manufacture the computer refused to boot no matter what voltage settings I had, so I was forced to leave the DRAM frequency on auto, I later switched to 2x4 ram sticks and they run without problems at the correct timings, so if you haven't tried having all ram timings and frequency on auto yet, try it and see if something changes

Do you run any software that will make use of this much RAM? I only ask because some people buy it expecting an increase in performance and are disappointed when they don't get it. The more RAM you have, the harder it is to overclock.

I would expect a QX9650 to go higher, my Q9550 which normally runs at 2.83Ghz is happily running at 3.4Ghz. (400FSB on 8.5 multiplier). I dropped my voltage from 1.25 to 1.175 and it's been stable as a rock.

Thanks. No, I don't really expect an increase in performance with 16GB. As a photographer, I edit & convert hundreds of RAW camera files & convert to jpgs. Each file is about 21MB, so it adds up. I'm doing quite well with 8GB of Ram, but I wouldn't mind doubling it & allocating some of it as a Ramdisk. Plus, I'm running a virtual disc, which I could assign more Ram to.

You probably have 2x4GB (only 2 dimms filled) of the G.Skill in your build - correct? That is probably why you can get a 400FSB with your Q9550. Plus, G.Skill will handle the increased speed. Kingston Value Ram can't handle it. I have 2Gb x 4, so all dimms are currently filled.

Overclocking is not as important to me as having a fast, stable PC with Ram to spare. I just got caught up in the mechanics of OCing.

From what I've learned, the CPU overclocking potential increases with faster (overclockable) Ram & fewer occupied dimms.

I believe I've learned my lesson.

One more thing (off topic) - high-end DDR2 is much more expensive than comparable DDR3!