Did you actually remove McAfee, or just disable it? We have found that some anti-virus products don't actually stop interfering if they are just disabled.

The fastest perfrmance is always with the data local, since the OS can manage the file bufferes for multiple workstation access. When the communication is "over the wire", the data must be delivered and refreshed continuously to make sure that chnges are actually reflected.

I'm still surprised at the discrepancy in posting times between local and the dedicated network connection. Is the server doing anything else?

The terminal server approach will be faster because of the fact that all the copies of the data are being managed locally.