Server: FMS 13 on OSX 10.9, 8 GB RAM
Clients: Safari 7, FireFox 25
Simple table, newly created in FMP13, 5K records, sub-summary by any text field.
Sub-summary (leading) followed by body part works well, sometimes very well. Remove the body part and server may peg one processor for several minutes. Sometimes I can get the report to show, usually not. For large tables, a report that takes 10 seconds on FMP becomes 10 minutes of waiting for the server to stop processing whatever it thinks it is processing. Attempts to log off the user seem to be futile until the process has completed.
Testing from a Mac using Safari 7. Same issue on FireFox (yes, I know this browser is not supported for some reason) but at least I get this message:
A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.
If I re-sort, I can typically view a few of the summary rows, but usually not all of them.