Oops, I made a blunder....... APIC, ACPI Trent said.........
A glance through the logs showed the debian kernel was having problems with the APIC.
Perhaps verify this experimentally, by booting with noapic.
Its the ACPI thats the issue, this being the same in the version of testing. I had a look around the net a couple of months ago when the previous version gave problems, everyone said the ACPI errors should not stop the kernel from working, it appeared though to be so (Note 1). In the custom kernel its disabled in the config, and it works like a dream. Note 1: Its difficult to say though, the custom kernels config is much simpler than the debian one and I have found in the past some options can have some real wierd effects. I have as yet not reported a bug as I like to verify there really is a problem and I cannot find anyone else on the net having an ACPI issue on Linux with the GA-X79-ud5 mb. Lindsay