Try the data=writeback option which emulates the way XFS handles log operations. With UPS and/or battery backed caching controller the risk should be minimum.
That will help, but ext3 is not good at handling large files at all, so if you can switch to XFS that will make a bigger improvement. Make sure XFS journal is set to max size and noatime and nodiratime are set to make regular/small file operations perform decently.
I just walked in that room and noticed some issues with that server so I may be rebuilding to new hardware! I will explore xfs on the rebuild.
Thanks everyone! jlc