I upgraded VMWare workstation 9 to 11 (build 11.1.2 - 2780323) before a month or so. Since then I was running into performance issues, especially, when I work with 3 monitors. I am not sure it was a hardware issue or software issue or combination of both. My VM host is Windows 8.1 with the latest updates and guest is Windows 10 RC.
I have docking station Toshiba Dynadock, which enables 3 monitors.
Eventually when I turned off 3D Graphics acceleration in VM Ware workstation settings, the performance improved with 3 monitors running.
This post might be helpful to someone running into the same issue and do not have any clue to fix it.
When Windows 10 RTM will be released, I will verify again by enabling 3D graphics acceleration; I guess by that time we may have some updates from VMWare too. Presently Workstation 11 is based on Windows 10 RC and they may get a chance to fix issues (if there are any) once Windows RTM is released.
I am still not sure what is causing the performance issue but at least I am okay right now and able to use 3 monitors comfortably.