this issue is not due to the fact you are running on amd especially now because all patching is done on the fly by the kernel. This is the main reason i suggested the vanilla install as you now will have no files pre patched for amd, or shouldnt have. I only suggested updating to 10.5.5 because we dont have an voodoo kernel to match 10.5.6. So by rights updating to a vanilla 10.5.5 would be as close to a real mac as you could get. Also i hope you did the updates straight through apple. Its interesting that the mouse is choppy is it a usb mouse? This could just be down to a usb issue or bios settings. Also have you got shared memeory added in the bios as nvidia cards do not like this you really need to disable this some systems wont even boot with this option enabled. Can you also tell me exactly which graphics card you have make model and memory?

---