Takes a long time to print in Citrix sesion

Hello,

While sending a print job (pdf) at citrix  session it takes up to 1 minutes to wait. 

Policy is very simple - just a print event registration only.

SDLP servers are 12.0, and agent 12.0.1 on terminal server. Citrix 6.5 and 40-70 terminal sessions simultaneously.

If agent is disabled (or shutdown), it takes less 10 seconds for sending a print job.

What I have to do accelerate a print job? Have a lot of claims from users.