I installed Sierra on Vmware (with some tweaks) but it does not support 3D acceleration.
Is there anything i can do to improve the performance of Sierra on Vmware? Would downgrading to El Capitan yield better peroformance? Is 3D acceleration supported on El Capitan?
Unfortunately Apple does not allow you to run a virtual macOS or OS X on non-Apple branded hardware.
You'll need to have apple hardware and use a product like VMware Fusion or VMware ESXi in order to legally run a virtual copy of macOS / OS X.
Hope you understand,