NFS Performance Help

[Wayne Hotmail]

Like others I am having issues getting any decent performance out of my NFS clients on FreeBSD.I have tried 8.3 and 9.1 beta on stand alone servers or as vmware clients. Used 1 Gig connections or a 10 Gig connection.Tried mounting using Version 3 and Version 4.I have tried the noatime, sync, and tcp options nothing seems to help.I am connecting to a IceWeb NAS. My performance with DD is 60 meg a second at best when writing to the server. If I load a Redhat Linux server on the same hardware using the same connection my write performance is about 340 Meg a second. 
It really falls apart when I run a test script where I create a 100 folders then create a 100 files in the folders and append to these files 5 times using 5 random files. I am trying to simulate a IMAP email server. If I run the script on my local mirror drives it takes about a one minute and thirty seconds to complete. If I run the script on the NFS mounted drives it takes hours to complete. With my Linux install on the same hardware this NFS mounted script takes about 4 minutes. 
Google is tired of me asking the same question over and over. So if anyone would be so kind as to point out some kernel or system tweaks to get me passed my NFS issues that would be greatly appreciated.
Wayne