Hi Mohit,
Please follow below steps...
SP01 --> Select a spool request --> Click on description of the spool and press F5 (Events)
To find out where the delay is (in SAP or at Network side?)
Second, check the spool work process log for any details that exists.
For SAPlpd logs please browse to path something like "C:\Program Files (x86)\SAP\FrontEnd\SAPgui\SAPlpd" and run SAPlpd.exe file to check the logs.
Check the output server queue is clear and is not stuck.
Check for inconsistencies in TemSe, and for any specific printer using SPAD -- printer name -- > Edit --> Clear cache.
Hope the above information helps you to tackle the slowness
Regards,
Prithviraj