What I have done, both in real installations and virtual machines is I make my 
/tmp and /var/tmp folders tmpfs. I have found, at least with KDE, the need to 
create and read/write hundreds of small files will slow down a system with 
poor iops. 

I have lately taken to running installations off the SDHC drive on my laptop 
and all is well and pretty fast, if I'm using a tmpfs /tmp and /var/tmp.

Try that in your VM, and like Lisa said, if possible, give it more ram.

Nathan




On Monday, March 11, 2013 06:48:12 PM Josh Coffman wrote:

Hi,


  I want to move all my non-windows dev to an ubuntu (or suggestion) virtual 
box vm. I'm noticing a sluggish UI both on ubuntu and Mint with cinnamon when 
running on my macbook. It's a retina with ssd and plenty of ram. I thought it 
might be unity until I tried Mint. Anyone know trick to speed up a vbox on 
mac?

Thanks,
Josh