damian: You can't just install the updates from the Software Updater usually, although 10.4.5 was cracked in a matter of days. I guess if it bothers you that you have to wait for what's almost always minor upgrades, it's not usable.
I know 10.4.3 had an internal iTunes universal binary, and applying the upgrade hosed the system. With 10.4.4 and 10.4.5 it may be possible to apply other software updates too. It's really a minor problem in the grand scheme of things.
Otherwise, compatibility is only severly lacking in Quartz Extreme/Core Image departments. Roestta works even if you have an SSE2 proc. Sound is touchy too, as NO soundblaster cards will work, although most onboard sound DOES.
http://wiki.osx86project.org/wiki/index.php/HCL_10.4.4
Take a poke around there and see if your hardware is supported specifically. Generally the "close enough" theory seems to apply.
refractor: The first part is referring to the patches you need: you can either find a base image and patch in SSE2 and AMD yourself, or patch in SSE2, and install the AMD enabler afterward. I'm a bit unclear on the specifics as I don't have any AMD procs, but it's just an extra step that can be performed in many different ways.
Disabling one of the cores is just in the OSX boot options, and a last resort at that. Windows will still work with both cores fine, those options are just to try on subsuquent boots if they don't work.
I'd be surprised if your processor is better supported EVER, unless maxxuss works more witchcraft and changes the way the AMD Enabler kernel patch work in future versions.
It's really a project to tinker with though, you have to do some decent research on issues so it's not for everyone, and the time-impaired as you seem to be.