Hi Adam,
Can you provide more details on what you are observing? UGS does query the server for changes every minutes but that should not be the problem. The number of query should be limited to a call to “p4 changes” followed by “p4 describe” for the new CLs. Are your users opening a uproject or uprojectdirs? Do they keep UGS open or they start it every morning?
Some logs from your server showing the bad conditions would also be useful.
Martin