Adding noapic and nolapic didn't work.

I still have kernel 2.6.18-5-k7 installed. As far as I remember I don't have these issues under that kernel.

I saved the dmesg logs from both kernels, seems like acpi/apic in the newer kernels doesn't like ATI chipsets that much.

Here are my logs:

dmesg-2.6.18-5-k7
dmesg-2.6.22-3-k7

There are a couple lines that didn't show up in dmesg under 2.6.18-5-k7

PCI: MSI quirk detected. MSI deactivated.

Marking TSC unstable due to: possible TSC halt in C2.

Maybe I should try noacpi or something similar?

Update: (if anyone is still watching)

I've tried adding noapic, nolapic, noioapic, noacpi, noirqdebug after the kernel in Grub, problem still happens.

I've even tried blacklisting drivers that I though might cause the problem:
blacklist cpufreq_conservative
blacklist cpufreq_ondemand
blacklist cpufreq_powersave
blacklist cpufreq_stats
blacklist cpufreq_userspace
blacklist powernow-k8
blacklist acpi-cpufreq
blacklist cpufreq-nforce2
blacklist e_powersaver
and still the problem happens.

One thing I did notice, it has happened once before, is that I came back to the laptop about 2 1/2 hours after being idle, and the problem was happening, but must not have been for long. CPU load was around 95%. I was able to slowly interact with KDE and it didn't completely freeze up. It took about 5 min after that for the CPU load to drop to normal operation.

Also at the moment SuperKaramba is reporting the CPU frequency as 1791 instead of 1800, which is odd, even though other CPU Identifiers see it has 1791.93 which is about right.

I also looked into a Bios update, but after reading the change log it doesn't seem worth it.

Update:

Ok I googled two days away in search for answers for this problem, and haven't come up with anything. It seems that since kernel 2.6.20+ people have had similar problems, caused by different programs, and no one has a real answer to why it happens or how to stop it.

Mine seems to be caused by SuperKaramba, and must cause Xorg to use more CPU power over time. So my way of avoiding this problem is I made a script to kill off Superkaramba and restart it every so often. Seems to be working fine so far.