Hello @Riana,
the slowness depends on many things, but I would make my first bet that it is slow just due to Java - JVM boundaries that are reached.
Here is what I would do, for starters:
0. Check if any non-SAS service/process is consuming your server resources. If any, manage it to give resources back to SAS.
1 . I would restart the middle tier, and before starting the services, I would clean/archive the temporary files (SASServerX_X\work \temp and \log)
2. Once it is restarted, if performance is still slow, I would recommend you to clean/archive your audit tables in WIP database ( http://support.sas.com/kb/58/599.html ), then restart the middle-tier.