Ubuntu only doesn't like apic

Whether 64-bit or i386, custom compiled or stock kernel, setup or actually in the distro, Ubuntu requires either noapic or pci=noacpi. That presents problems and trade-offs that don't make Ubuntu a viable option. Slackware works without the need to disable anything, and according to a Gentoo user on Linux on Laptops, neither does Gentoo.

This is the working config I use in Slackware that I also used in Ubuntu: 2621-HP.config
With the default parameters, Ubuntu will freeze as it loads GDM, so it hangs at a black screen. In single user mode, with apic enabled, it will still freeze. Without quiet nosplash it might hang at loading the drivers or "setting up console font and keymap".

If I disable apic, change xorg.conf to use the vesa driver, then boot normally, loading GDM no longer results in a black screen, it actually comes up and I can log in. However, it still freezes completely about a minute or two after.

'noapic' = Ok, the machine boots, everything works, except for USB. So adding irqpoll will fix the USB problem.
'noapic irqpoll' / 'noapic irqpoll noirqdebug' = Machine boots, but there doesn't seem to be any power management or cpu frequency scaling. The CPUs are constantly running at full speed. No battery detection, etc etc.
'pci=noacpi' = Big fat X11 error message trying to use the accelerated nVidia driver, a problem relating to edge-triggered IRQs.

I'd like to stick with Slackware, but I need a distro with a package manager. I have some logs zipped up, including from Slackware, and lspci -vvvv from Slackware. I hope they're enough to go on.

This is the computer: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00847924&lc=en&cc=us&dlc=en&product=3340175&lang=en
w/ latest BIOS

Currently I'm using Ubuntu Feisty 7.04 64-bit with 2.6.20-15 and 2.6.20-16 kernels installs. The 32-bit build isn't any different.

processor : 0
vendor_id : AuthenticAMD
cpu family : 15
model : 72
model name : AMD Turion(tm) 64 X2 Mobile Technology TL-56
stepping : 2
cpu MHz : 800.000
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic cr8legacy ts fid vid ttp tm stc
bogomips : 1608.35
clflush size : 64

processor : 1
vendor_id : AuthenticAMD
cpu family : 15
model : 72
model name : AMD Turion(tm) 64 X2 Mobile Technology TL-56
stepping : 2
cpu MHz : 800.000
cache size : 512 KB
physical id : 0
siblings : 2
core id : 1
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic cr8legacy ts fid vid ttp tm stc
bogomips : 1608.35
clflush size : 64