Overclocking help - stubborn FSB speed

[thegrimfandango]

Hi folks,
I'm relatively new to overclocking, I've been getting as much advice online as possible and trying small tweaks, and I'm hoping someone can help me.

I currently have a middling gaming rig with:

Gigabyte X38-DS5 motherboard (reported as DQ6 by CPU-Z)
Intel core 2 duo e6600 cpu
8gb (4x2gb) Corsair dominator DDR2 ram
Corsair 650w PSU
Geforce 9800GTX+ gpu

The stock speed for the core2duo is 2.4GHz, but I know it can be higher than that - at the very least I should be able to push 3.0GHz with it.
However, no matter what I tweak in BIOS, CPU-Z, Coretemp and other programs only report my core speed at 2.4GHz. I have noticed that this is because the FSB bus speed stays at 266MHz, no matter what it is set to in the BIOS.

Currently the BIOS (MB intelligent tweaker) shows setting of 333MHz for FSB with a 9.0 multiplier, giving me a CPU core of 3.0GHz
RAM is set to 800MHz on 5-5-5-15 timings.

I've tried pushing up the FSB overvoltage to +0.2 from +0.15, and the CPU vcore up to 1.475 from 1.35 (I'm aware this is high, but I wanted to see if it would make a difference then drop down in increments.)
Makes no difference - under stress testing I am stuck with 2.4GHz as the FSB speed won't show the BIOS changes.
I'm at a loss.
Temps are fine, and all the settings I could find in BIOS that automatically throttle are disabled for testing - still 266MHz or nothing. BIOS settings are definitely holding and not resetting on reboot.
Anyone know what I'm missing?

EDIT: Cleared CMOS and re-overclocked. Again, BIOS looks good, under stress testing , CPU resolutely refuses to go above 2.4GHz due to Bus speed.
(Captcha: Technicolor yawn. Lol, gross)

 

[CAPTCHA]

What are you using to read clock speed?

Assuming your readings aren't lying to you, it might be to do with your memory. Try increasing the frequency a bit (also, what frequency are they? Do they have any slack?).

Expecting to get 3.0GHz from your overclock might be pushing it. I'd only aim for an increase of 0.2 to 0.4 to start with or you risk cutting your life expectancy pretty hard.

 

[thegrimfandango]

CPU-Z, coretemp and another benchmarking program (the name of which escapes me as I'm not at home) all show bus speed of 266MHz.
Literally everything else I change in BIOS shows correctly - multipliers etc in these programs.

I know I can get 3.0GHz stable as the PC was built for me by an ex-coworker at the LAN gaming centre I used to work at and all the PCs were clocked to that with the same components.
Mine was also overclocked by him to 3.0GHz stable for most of a year until about a month ago when I had HDD problems and bluescreening.
Those issues are resolved now, but at some point the BIOS got reset and I had to 'redo' the overclocking.

I have however, tried smaller overclocks like you suggested, but I can't even get 2.6 or 2.8GHz as the bus speed stays stuck at 266MHz when I boot into windows.

I can't even live with this and increase the multiplier to get a higher clock speed as the highest multiplier my motherboard will allow me to set in BIOS is 9x
I've also tried lowering the multiplier and increasing the FSB to no joy.

RAM frequencies and timings are where my knowledge starts to run thin regarding how it relates to other settings and overall performance balance- the RAM is rated to 1066MHz.
I've tried running it at 667MHz, 800MHz and 1066MHz (and a little above) mostly with 5-5-5-15 timings. I have tried others but I'm not sure how to adjust them - what do you mean by slack?
Still no change to the bus speed in windows.

It has been suggested that I completely wipe & reinstall my OS as the BIOS looks fine and maybe something in Win7 got messed up with cloning and switching of HDDs - worth a try?
I'm reaching the end of my tether as I only got this part as I was assured it overclocks well and it's now pretty useless for modern games.

Last night I updated my BIOS, completely reset CMOS (left battery out overnight), loaded failsafe defaults, rebooted. Loaded optimised defaults, rebooted, then started overclocking again this morning. Again - every BIOS change holds in windows except bus speed

 

[CAPTCHA]

-snip-

Sorry, I'm not being too helpful but are you saying that the clock settings are resetting after you boot or is it simply refusing to acknowledge that any changes have been made?

You know it might just be the CPU. Not all CPUs are built equally and the frequency they can handle can differ batch-by-batch. I'm hoping that it's not just a dud chip though.

Let me have a think about it and I'll get back to you if I come up with anything.

 

[CAPTCHA]

Something to try:

If your multiplier is capped, try lowering it and increaseing the voltage and FSB a tad. Make sure your RAM is adjusted to match.

 

[thegrimfandango]

Thanks for trying to help me out. The clock settings are not resetting - I can look at the BIOS anytime and see my overclocks, it's just that the setting for fsb speed is being effectively ignored(and only fsb speed - changes to multipliers etc ARE reflected in diagnostic tools after boot).

I have tried lowering the multiplier and increasing fsb, it just gave me a lower clock speed as the changesto fsb weren't acknowledged.
It's really weird, I can find a few other people who had the same problem over the years online but no clear solution that I havn't tried.
It could be the hardware I suppose, but it's not old and well looked after, as I said, was previously overclocked and the CPU is a known good overclocker. I hope not, as I can't afford to replace the mobo, and if I did I don't know if it would be worth my while buying another DDR2 mobo, which means replacing all my RAM too - way outta my budget.

Something else I noticed (when I finally got the screen to stay up long enough) - The POST screen during boot also refuses to reflect changes to fsb speed and will only show 266MHz x whatever multiplier I pick, though the PC boots first time and shows no indication of failing POST.

 

[thegrimfandango]

Ok, I seem to have fixed it (I hope) but as to what was causing it...

I powered down pulled PSU & all my RAM sticks from mobo, cleared CMOS again and booted into BIOS.
Tried a tiny overclock to 270MHz...the overclock held in windows.
Replaced another RAM stick, made a few more tiny adjustments..no dice, back to 266MHz.
Cleared CMOS again and started from scratch, overclocking to 270 and leaving it there, then rebooting and adding one RAM stick at a time until I was back up to 8gig.

Started overclocking in increments and I now have the PC running at 3.0GHz (333MHzx9)
RAM at +0.2v , PCI & FSB at +0.1V and Vcore at 1.35V (stock CPU voltage)

My RAM is running at 800MHz in a 5:6 ratio with 5-5-5-18 timings. I left the timings on auto, but I'm wondering if these could be improved at all.

 

[CAPTCHA]

-snip-

Sounds wierd. I wonder why it started to work again? Dodgy RAM bus perhaps?

Anyway timings are pretty simple if you want to try tightening them up a bit. Basically the different numbers (5-5-5-10) refer to the columns and rows in which bytes are stored, while the values of those numbers refer to the window of delay the memory has to provide the information in said column/row.

If your timing are too slow, the CPU idles. Too fast and you can cause a data overload, causing your accumulators to miscalculate and crash.

Just try lowering the timings a little and running your computer. If you notice a lot of hang ups and crashes, reel a timing or two back a bit.

Handy link: http://www.overclock.net/t/26706/info-ram-timings-for-dummies

 

[thegrimfandango]

Who knows, if the setting are bad it should fail POST and reset, not just pretend some settings don't exist.
Thanks for the advice on RAM timings, that was one thing I found pretty confusing.