VMware Fusion users running OS X Yosemite in a Fusion virtual machine have reported graphics performance issues, especially in comparison to running previous OS X versions in a Fusion VM.
The Fusion engineering team identified the root cause as an issue with beam synchronization, which Apple introduced in 2007 to improve screen redraw and window management in OS X.
We’re working hard to deliver a fix. Until the fix is released, here’s a customer-suggested workaround to temporarily disable beam synchronization. Making this configuration change will significantly improve graphics performance when running OS X Yosemite in a Fusion VM.
Thanks to @rtrouton for his blog post on the subject, and many thanks to VMware Fusion users for your support and patience while we work on this fix.
Best wishes for 2015!
–The VMware Fusion Team