So you just upgraded your Ubuntu box and found that all your VmWare Windows Boxes are extremely slow?
The symptom is your Windows task manager showning 100% usage of your disk, and the WIndows Instrumentation showing very long lags, says, up to 2.5seconds (yes, seconds) to respond to a disk request. This makes the box practically unusable.
Perhaps your vmware logs are shoing a lot of lines like
scsi0:0: Command READ(10) took 2.748 seconds (ok)
scsi0:0: Command WRITE(10) took 3.224 seconds (ok)
and so on...
Well, this is a well known issue. A quick search with google will point you to the vblank_mode=0 fix.
Indeed I already fixed that on my box, my /etc/profile file already exported it.
But for some (obscure) reason, it doesn't work anymore. Again, a (this time) long search will point you to the correct answer: [this post](http://stackoverflow.com/a/29329265/4000694) suggests to check another variable if you are using closed sources drivers for Nvidia, __GL_SYNC_TO_VBLANK=0.
Indeed this worked very well. I don't know why it changed, I suspect that the Ubuntu upgrader silently changed from open source to closed source drivers. Perhaps I tried them and when I switched to Open Source drivers, something remained. Really, I don't know, if someone has the response, please share it.
Now my Windows Boxes are fast enough to be used; now I have to deal with Windows Updates, but this is yet another story.
