By remote, I assume you mean client. And the clients requirements will depend on the Operating System of the client, and how you are connecting.
Generally speaking, so long as the operating system has met it's requirements, the Citrix client should have enough operating space to function. The client has a very low memory and processor utilization, with the bulk of the load on network/IP traffic.
If the client is locking up, try checking the client configuration. Lower the screen resolution, color depth, and turn off sound integration. Check that you have the latest version of the client installed.
You can also shadow a session to see if the application being run has frozen, then you can start troubleshooting the server-side.