I'm (obviously) not very knowledgeable on the subject.
When I do some intensive GIMP manipulations, the CPU-usage according to conky only goes to about 33%, on my triple-core. I'm pretty sure GIMP can use multiple cores (but not sure all of the actions of GIMP can use multiple cores).
I've done some noobish overclocking via the BIOS. So that might be a problem...
(IIRC it never run higher than 33% before.)
I don't have to download a special SMP version of Linux, I assume. (PC runs Debian Squeeze.)
I have dual channel memory, so that means that theoretically I should get at least 66%, right? (But again noobishly clocked.)
Would anybody know a way/program to verify my bottleneck (memory?) and/or problem (damage? misconfiguration?)?
Reading this, makes me want to try to run normally clocked for testing... :-/

Check the 'top' command. Additionally, to monitor the utilisation of all the cores, you can issue:
or
Where x is the x seconds interval the check should be performed.

If you want to check if you RAM isn't faulty, please run memtest86 (Last time I run it it was from an Arch installation CD.)


Edit: In GIMP's preferences you can set the number of cores that gimp should use. Check what is set there.

Thanks for the post. GIMP is set to three cores. I will run memtest later. mpstat is not installed, nor is it a package available at the repositories I've selected.

If you are a noob to that, as you state more than once, you shouldn't overclock at all until you gathered the required knowledge. Otherwise you can get anything from simple malfunctioning to fried hardware.


No, Debian runs a SMP-enabled kernel by default.


No, how many channels you memory controller supports/uses is totally unrelated to this.

mpstat is part of the package sysstat, which is in the repositories.

...as I have recently experienced Fortunately it seems to have been the former.

I'd doubt that an overclock is stopping you from using multipule cores. As an aside, I wouldnt be overclocking Athlon X3 CPUs these days, faster Phenom II X4-X6s and Athlon II X4s are very cheap now...

Have you set GIMP for multicore use?

http://www.graphics-muse.org/artistsguide/?p=267

That wont get GIMP using 100% of cores on 100% of operations, but it should give some improvement.

The simplest program I've found that uses multiple cores is "make -jN", where you replace N with the number of threads you want. All the cores work