after a bit of research (ie. Google), it seems there's no way to disable Cool'n'Quiet on my mobo :(

@ Rogue, do you have an option for CnQ in yours, If so is it enabled?

What kind of motherboard do you have?

EDIT: Found it in your account infos. Which version is it? there are three different.

EDIT2: Here is the manual for the version GA-K8NF-9-RH. I presume the BIOS versions are rather similar.

EDIT3: I Checked the BIOS setting and the complete manual, not a word about Cool'n'Quiet. This is crazy.

Have you tried to disable all unneccessary devices? Today this could be Floppy controller, LAN Boot ROM (is your onboard LAN working?), Parallel Port, Modem Port, Gameport, MIDI Port. If you use a PS/2 mouse and keyboard, I would set all three Legacy USB options to 'disabled'. In the 'MB Intelligent Tewaker' settings must be an option 'CPU Spread Spectrum', disable it.

C'n'Q is located in the Cell menu on my motherboard. Mine is enabled because I don't want my system running at full CPU when in an idle state or merely just chatting and surfing.

mines the Rev 1, onboard lan is disabled... In theory most of the options you've suggested shouldn't make a difference if they're enabled or not since the machine is fine running cpus=1. I'll give disabling the spread spectrum a go to see if that helps at all though.

Voyn1x, on your mobo under M.I.T. you have an option named 'K8 CPU Clock Ratio', if that is set to Auto then C'n'Q is enabled, if you've changed it then it's disabled.

With idlehalt=0 and cpus=1 I am still having the mouse stuttering bug, more so when Transmission is checking data on an existing torrent. Large file transfers seem to be smoother though.. Still, the mouse movement still stutters. This is in Leo4Allv3 10.5.3.

3 days 12 hours uptime with cpus=1.

Stable as a rock for me. Using Leo4allv3 10.5.3.

can't understand it, it works great on my Opteron. Have you tried boot option -legacy? This are my com.apple.boot.plist settings:

<plist version="1.0">
<dict>
<key>Kernel</key>
<string>mach_kernel</string>
<key>Kernel Flags</key>
<string>-legacy</string>
<key>Timeout</key>
<string>3</string>
</dict>
</plist>

I deleted ALF.kext on my system, also all other gfx drivers which I don't need for my own card (Radeon X1000 series).

I think you've got a different issue there, could be something to with your hard disk/network drivers. Do you have any other symptoms? Apps quitting etc..?

I get the 1080 error in Zephs after awhile, iChat crahses a lot. Leo4Allv3 seems pretty stable app wise, but the mouse bug is worse I think.
I have a Buffalo WLI-12 wireless nic (broadcom chipset), I did not install the forcedeath kext for the nforce LAN, and I have the marvel LAN installed. (DFI Ultra-D mobo) The bug never shows up till torrents are being checked or I am transferring large files. I'm confused.