[Mr_Snood]

4 Minutes sounds not bad.

It may take a second until the PartPoker client delivers the playerlist of a table and then again 1-3 seconds to search your database for the statistics of the players.
So to scan a table may take 1-5 seconds (or more if your database is realy big).
Now you can compute how long a FullScan may take if there are 20-30 tables available...

In fact the first scan should be always the slowest,
but later scans should be a lot faster, because the data from the first scan is "reused"...

The only way i can think of what is causing your "later" scans to be much longer is, that the data from the first scans is compromising your CPU too much.