[CentOS] 3ware 9650 issues

I've been having no end of issues with a 3ware 9650SE-24M8 in a server that's 
coming on a year old.  I've got 24 WDC WD5001ABYS drives (500GB) hooked to it, 
running as a single RAID6 w/ a hot spare.  These issues boil down to the card 
periodically throwing errors like the following:

sd 1:0:0:0: WARNING: (0x06:0x002C): Command (0x8a) timed out, resetting card.

Usually when this happens, it's followed by:

3w-9xxx: scsi1: AEN: INFO (0x04:0x005E): Cache synchronization 
completed:unit=0.

On the less pleasant occasions, it's followed by:

scsi1: ERROR: (0x06:0x0036): Response queue (large) empty failed during reset 
sequence.
3w-9xxx: scsi1: ERROR: (0x06:0x002B): Controller reset failed during scsi host 
reset.
sd 1:0:0:0: scsi: Device offlined - not ready after error recovery

This of course leads to a several hour downtime as the system has to be powered 
down (not just rebooted) and then the volume needs to be fscked. I've been back 
and forth with both the vendor and (via the vendor) 3ware with this.  The card 
has been replaced, as well as the whole system.  I'm running the latest 
firmware and drivers from 3ware.

Have other folks had good luck with this card?  What sorts of configs are you 
running?  I'm in the position of needing more storage, and I'm a bit gun shy on 
3ware at the moment...

-- 
Joshua Baker-LePain
QB3 Shared Cluster Sysadmin
UCSF