BTW.: applying "pci=conf1" as boot option sometimes helps
(mostly for multi GPU multi CPU setups, but you may give it
a try nevertheless).
Concerning realtime preemption, have checked the following thread
http://www.nvnews.net/vbulletin/showthread.php?t=70776
and applied the appropriate patch to the nvidia driver?
Concerning high latencies with realtime preemption: the nvidia4
SATA controller can cause latencies up to 16.6ms (seems that
there is no way to easily fix that in software). Maybe the ATA
controller is also affected.
regards
Bernhard