I'm wondering what might be the cause for a big slowdown in a small app I have. Here's the scenario:

1) I have a FOR loop which iterates about 500 times, and repeats as many times as needed inside a WHILE loop, possibly 2,000 total loops.
2) In each FOR iteration, I do an SQL into a cursor from a table of 200,000 records, with a WHERE clause on 10 indexed fields. The cursor has about 5,000 records each time, less than 1 MB in size. Then I SCAN the cursor several times, doing some string manipulations and comparisons with STUFF & SUBSTR.
3) Some results are displayed and constantly updated on screen.
4) This should take less than 2 hours on a 180 with 32 RAM...according to the processing rate for the first 1/2 hour or so. It starts very fast, then it slows gradually down, and after about an hour it's VERY slow, just crawling.
5) According to the Resource Meter, memory use is unchanged from start to finish, and there really is not much to put in memory here - even the table is quite small, using only 10 Integer fields. Nothing else at all running.

Any ideas what might cause this, or a cure for it? I get exactly the same results in vfp5.0a or 6 beta.