NFS question

[Kay Nettle]

We have around 100 Linux boxes that get home directory service from a 
Sun ultra enterprise 4000.  We've started doing RAID5 on the Sun and 
have noticed a x4 increase in NFS writes.  The problem seems to be 
specific to RAID5, we have a couple of RAID0+1 disks and we do see a 
small performance hit, it is nothing like RAID5.  

Are there any NFS patches that might help with this problem, or are 
we just screwed?  

Thanks,
Kay