I think thats enough google bait in the title.
Using VMWare 8.x on El Capitan (OSX 10.11) with Windows 10 can be quite slow - this is a known (and un-addressed issue) with VMWare Fusion 8.x - and worse, VMWare have down-scaled their team, so it's unlikely to be properly fixed.
After a bit of googling, here's some things you can do to make it a bit quicker. Your VM will need to be shut down for this, and for the VMX changes, you will need to quit VMWare.
First, turn off 3D acceleration in VMWare settings (Virtual Machine → Settings → Display → Untick Accelerate 3D Graphics). (I'm not 100% convinced about this one yet, I'll try it in both states)
Next make the following changes to your VMX file. The file in contained inside the
Windows 10 x64.vmwarevm), so right click on it, select
Show Package Contents, and edit
Windows 10 x64.vmxwith any text editor.
mainMem.backing = "swap" scsi0:0.virtualSSD = 1 MemTrimRate = "0" sched.mem.pshare.enable = "FALSE" MemAllowAutoScaleDown = "FALSE" logging = "FALSE"
There is an explanation of these here.
If you have more than one disk, add another
scsiN:0.virtualSSDline as needed (the CD drive doesn't need it)
Then start up your machine and see if it makes a difference.
The extended mitigation is to get Parallels, which appears not to have the same problem.