I can confirm that the GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.modeset=0 noplymouth" workaround works on my thinkpad t60. No dropouts anymore!
I can confirm that the GRUB_CMDLINE_ LINUX_DEFAULT= "quiet splash radeon.modeset=0 noplymouth" workaround works on my thinkpad t60. No dropouts anymore!