Yes, this solved the issue. Thank you.
After a reboot without Xen, so with the regular Arch kernel, the microcode does get applied.[arthur@orion1695 ~]$ dmesg | grep microcode
[ 0.900044] microcode: CPU0: patch_level=0x0600081c
[ 0.900056] microcode: CPU1: patch_level=0x0600081c
[ 0.900069] microcode: CPU2: patch_level=0x0600081c
[ 0.900079] microcode: CPU3: patch_level=0x0600081c
[ 0.900090] microcode: CPU4: patch_level
I am a so new user of Ubuntu I still have the fresh car smell :) I am trying to install Ubuntu 12.10 on my HP Pavilion dv7 AMD quad processor laptop.