as I've said earlier - there's no way for me to modify RAM timings. I wonder if this could be connected with absense of QE/CI (still I have to choose - QE/CI or menus. I do like menus).

@Ian: Hey alright, you don't have to get all fussy about it. It's no offense to you. I'm just a bit frustrated because myself and others have been ignored on this issue for a while now, and it seems that having to change memory timings from default values is not a proper solution if there is something that should be fixed within the release itself. Additionally, I am a bit skeptical because this was never an issue before in previous versions of OSX, so why Leopard? Anyway, we have the same brand/make of RAM, I think. I'll give it a try and report back. Sorry for making waves in your lake.

Thats okay I've got frustrated for similar reasons in that I keep telling people this fixes the issue and no one tries, appoligies to people who can't/don't have settings in bios.
I didn't have issues with tiger either, only leopard.

I should add its a bit of a bugger for me I usually run my memory oc and it score 166 in xbench now down to 130 ish.
But hell it works

Also add
firefox used to quit on me occasionally doesn't seem to be doing it any more can't swear its related but guessing that it is.

Thanks for sharing the knowledge. I just got back from changing the settings, so I'll make it my duty to report back here and share my experiences with everyone on this. I haven't done a bench test yet. I was on full default (no OC) in BIOS before this, so it would be a bummer for me too if I lose some performance because of the new settings. The hard thing about this for me too is that I can't tell what initially causes the slowdowns. I can have my computer on for 3 hours or 18 hours and it always seems different, but it's most likely to happen if I leave my system on overnight. I'll try experimenting with different programs and whatnot. Thanks again.

Cool look forward to your input

Next time you'll catch this one log the state of WindowServer process ('ps aux' in console), something like:
_windowserver 555 1.5 0.8 389596 17540 ?? Ss 10:20PM 0:03.47 /System/Library/Frameworks/ApplicationServices.framework/Frameworks/CoreGraphics.framework/Resources/WindowServer -daemon
I feel it's the problem. At least when I've killed it ('kill -9 <PID>', 555 in the line above) - everything got back to normal. Still I don't know the OSX process tree yet, so I feel like killing X11 on linux and all GUI stuff with it. Anyways, this is somewhat faster than reboot

hmph. Got macports and pstree. Seems that WindowServer is not spawning anything on its own (I could guess that). Ok, the only way to find the bad guy is one-by-one shotoff

@farcaller, thanks for the info. i never knew about that.

@Ian, i did three different bench tests after changing the memory timings (xBench, OpenMark, and OpenGLev). everything seems normal. again, i never had any OC settings in my BIOS, so for me, changing the memory timings doesn't seem to have caused any drawbacks so far. all in all, system performance seems the same, so really it's just a matter of long-term testing to see if the slowdowns come back. as i said, i'll keep this thread updated after i've left my computer on for 24+ hours. in the meantime, i will be going back to all of the posts on this forum where this subject has been discussed, and i'll try to rally everyone to this post. we'll make it a somewhat "official" post for this bug and see if we can all try to work together on figuring it out. maybe we can even get enough attention from Zeph so that he might look to the internal workings of leopard for some solutions.

How many people who are suffering from this also have random crashes from firefox, for me I'm pretty sure the issues are related?
Also this bug used to come on if I downloaded/uploaded a lot.
Are these the things other people recognise?

Same problem here after running for a while mouse goes mad like its on d***s jumps to corners and so on, i cant say that i have noticed a system slowdown as such as i always reboot when the mouse goes off on one.tried the memory timing thing to no avail.reset bluetooth tried different mice all produce same mad mouse movements.
i dont use firefox so cant check crash problem..
Firewalk