Replace field always (from my experience) is slow. Practically the same like script looping through records.
And it doesn't matter how high is computer speed, RAM size or computer OS.
Once I use Lookup from global field - it is faster.
For a single field, replace should be faster than a loop. Text vs. number I don't know but would guess that numbers would be faster if there was much difference at all.
Are you replacing with a fixed value, or a calculated value? Are there other fields that lookup or recalculate based on the replace field?
Try using a script that includes Freeze Window. Also, go to a simple or blank layout based on the field's table -- that's right, the field doesn't even need to be on the layout if you're using a script -- and make sure the layout is in Form view (not list or table).
The main thing you must do to make Replace faster is to use a layout that is in Form View. It can either be that way to start with, or you can flip it to Form View, then flip it back to whatever it was.
If you do not know what it was to start with, you can capture that into a script Variable, using Get (LayoutViewState), then use an If test to restore it.
Also, use Freeze Window at the start. The user should not even see the view changing (at least on a Mac).
It is important to use Form view, especially on FileMaker 11. I've seen scripts which were much slower on 11 (mostly Loops) actually go faster than FileMaker 10 if optimized as above.
Tom, Thanks. I went back and checked and I did have a number of calculation fields that referenced the field and then had summary fields that referenced the calulation fields as well so I'm rewritting to get around the problem. Quick test did resolve the issue!