Citrix and Performance: We have been using GuiXT trouble free for a long time. Now, having recently introduced a Citrix server environment, we have noticed a performance degradation. What could be the reason?
There are a number of productive installations that successfully use the combination GuiXT + Citrix; no general performance problems have been reported so far. We suggest you check the following:

If you use SAP Web Repository or SAP Mime Repository to store the scripts it is important that the GuiXT cache mechanism is working. 

In addition, use the "VersionNumber" statement (see documentation) to minimize the script downloads. And verify that the cache folder ("Directory0" in is not cleared with each logon on the Citrix server.