Hello!
this fix worked fine 4 me.
open terminal.
Type: sudo nvram boot-args="debug=0x10"
press enter.
insert your password.
Reboot
I fount in another post.
Here
fusion 6.04 with Yosemite GM very slow
Enjoy.
Reason for this debug code instated of D4E, it that D4E enable all debug option, and you don't need this.