Overclock problem?

I've overclocked my Q6600 from stock speed to 3.2GHz. Everything seems fine, voltages are alright as well. It shows at POST that its running at 3.2 but in windows it shows its still at 2.4 and in cpuz it core clock speed keeps changing from 2GHz to 3.2GHz. Here are the screenshots





In the second screenshot, you can see core speed is 2GHz

what can be the problem?

For the numbers showing in CPU-Z : just go in your power options and set it to
High Performance.
I stumbled over that when I got my last (this) computer and saw those numbers fluctuating


Only Difference I have an Athlon and there it would rather fluctuate the multiplier than the core speed
-DG

If you have C1E stepping enabled in the BIOS, make sure you disable this. This is highly recommended when overclocking for stability reasons.


J

EzioAuditore said:

Apart from C1E option, this can also happen when there's no need for such core speed i.e. it's also depends on the work load.
For eg. download RealTemp, open it and run the XS Bench (clickable button), you'll notice that core speed would have reached to highest i.e. 3.2 (which you've set) and after the benchmarking, it'll come down.

Good point, should have also mentioned this, i.e. Speedstep. This is more what the OP is talking about rather than C1E. Speedstep reduces your clockspeed dependant on load like you describe.

Personally when overclocking I disable both C1E and Speedstep, but this isn't necessarily a requirement, it just helps with stability at higher OC's. It does of course mean a slightly higher power consumption continuously, i.e. even when the CPU is not in use.


J

@ Devilz

The answer is simple math.

The default FSB for a Q6600 is 267 Front Side Bus and the default multiplier is 9 which is 9 x 267 = 2403 or 2.4Ghz Default.

You have overclocked the FSB to 400 and the lowed the multiplier to 8 which is 8 x 400 = 3200 or 3.2Ghz.

Correct?

Now, Windows will always use the default FSB for your CPU (no matter what the overclock is) but use the modified multiplier value (weird but true) so Windows sees your CPU as 267 (default FSB) x 8 (modified multiplier) = 2136 or 2.13Ghz as shown in your Windows system information Q6600 @ 2.4Ghz 2.13Ghz.

Just to see if my answer is true, try going back into your BIOS and change the multiplier to 7 while keeping FSB at 400, boot into Windows and your system information should be shown as Q6600 @ 2.4Ghz 1.87Ghz.

End phrase, not to worry as long as CPU-Z shows your CPU is running at 3.2Ghz your overclock is successful. And the fluctuation in your CPU just means is going into low power mode (C1E in BIOS and Power Options in Control Panel > Minimum Processor State), it has nothing to do with the overclock as long as your system is stable.

Nemix77 said:

@ Devilz

The answer is simple math.

The default FSB for a Q6600 is 267 Front Side Bus and the default multiplier is 9 which is 9 x 267 = 2403 or 2.4Ghz Default.

You have overclocked the FSB to 400 and the lowed the multiplier to 8 which is 8 x 400 = 3200 or 3.2Ghz.

Correct?

Now, Windows will always use the default FSB for your CPU (no matter what the overclock is) but use the modified multiplier value (weird but true) so Windows sees your CPU as 267 (default FSB) x 8 (modified multiplier) = 2136 or 2.13Ghz as shown in your Windows system information Q6600 @ 2.4Ghz 2.13Ghz.

Just to see if my answer is true, try going back into your BIOS and change the multiplier to 7 while keeping FSB at 400, boot into Windows and your system information should be shown as Q6600 @ 2.4Ghz 1.87Ghz.

End phrase, not to worry as long as CPU-Z shows your CPU is running at 3.2Ghz your overclock is successful. And the fluctuation in your CPU just means is going into low power mode (C1E in BIOS and Power Options in Control Panel > Minimum Processor State), it has nothing to do with the overclock as long as your system is stable.

Whilst I would tend to agree with you that what Windows shows can be different from CPU-Z, if you see the screenshots in the OP, this is also showing the lower clocks in CPU-Z therefore we are definitely talking power saving or CPU stepping in this case.


J

It's simple, when the computer is doing nothing it'll try to save power.

Unless your disable C1E in BIOS or change Minimum Processor State to 100% in Power Options.

It has nothing to do with the overclock, as stated above. Generally it's better to keep C1E and Minimum Processor State at 5% as this helps reduce power when computer is doing nothing and also keeps your CPU cool and quiet thus prolonging the life of your CPU. But if you run into stability problems with your overclock then usually disabling C1E helps and if you just want to show your CPU at the highest overclock value at all times in CPU-Z then changing Minimum Processor State to 100% takes care of that.