AMD64 kernel hangs during boot process

Completed vanilla installation of 5.10/AMD64 with default uniprocessor kernel.
Entered GNOME and accepted immediate upgrade of all pending update packages.
Rebooted system.
Launched Synapted Package Manager, selected, downloaded and installed package
"linx-image-2.6.12-10-amd64-k8-smp", which completed auto-configuration into
grub OK.
Rebooted system.
Server defaulted to new SMP kernel image.
Boot process proceeds as far as the display of "ubuntu"+logo and the text
"Loading Modules..." with the dark brown horizontal bar.
No further progress after that point.
System does not respond to soft reset and requires hardware reset switch to unlock.
A return to uniprocessor kernel and the machine boots perfectly [select via grub
menu].

WindowsXP works OK [both CPUs] on same hardware. Will check other Linux distros
if time permits.
Will also check /var/spool/messages and post anything interesting.

Very happy to experiment - nothing of value in this build [can trash and
re-install as required].

Hardware:
Tyan Thunder K8W
2 x Opteron 250s
4Gb PC3200 RAM
XFX GeForce6800 Ultra
Creative Audigy2 ZS
Adaptex PCI SCSI
HP DDS Tape