In IRIS, every time a request need to be processed, a specific IRIS process (IRISDB.EXE) need to be assigned to handle that request.

If there is no spare IRIS process at that time, process will need to be created (and later destroyed). On some Windows systems (especially with security/antimalware solutions being active) creating new processes can be slow, which can results in delays during peak times (due to inrush of requests).