Screen Refresh Lag (Opening & Closing Applications Windows 7 Virtual)

I am having an issue with a screen refresh issue when I have my thin client programmed with a windows 7 virtual environment. I have tried changing the resolution increasing the refresh rate etc. The funny thing is I only have this issue when my terminal is programmed for a Windows 7 VM. When I have it programmed for a Windows 10 or for a server environment such as windows server 2008, I don’t experience the same issue. I have also tried increasing resources on the VM 7 machine such as adding more cores and RAM, and the result remains the same. Any ideas would be helpful.