Poor File Server Performance

I had a problem where excel, word or mp3 files on my file server were taking
a long time to close and open (up to 5 minutes). Had no problems with txt
files or using Open Office to open excel or word. After dealing with
Microsoft to no avail, finally rebooted the server and this appears to have
fixed the problem. When I told the tech this, he thought the problem was a
temp or cached file. Nothing was showing up in the event viewer and no
performance issues were seen using Task Manager. I currently have the File
Server set to Maximize data throughput for file sharing, but have been
reading some articles about cached files and they suggest that I change it to
Maximize data throughput for network applications.

Does anyone have any suggestions on whether this is a good idea or have any
other suggestions so that I can avoid this problem in future?

Thanks -- Dee