Hello usmguy,
Please check the security logs for excessive failed login attempts, it could be a brute force attack affecting performance if the RDP is exposed to the Internet.
Also, update the NIC drivers on the hardware kit and if possible run SFC and DISM image restore to make sure the OS files are intact.
Lastly, check perflogs CPU utilization, disk and NIC utilization and backlog.
Regards,
Miguel Fra
www.falconitservices.com