Blender Lag - Quick Fix
Lately, I've been using Manjaro Linux and I've noticed that whenever I use Blender 2.69, its interface lags and I would be discouraged from using it and just use other software on my Win7 virtual machine.
However, through very little tinkering, I found that the fix is to simply change the "Window Draw Method" under the "System" tab in the "User Preferences" from the default "Automatic" to "Overlap". That's it! Instant fix.
As a side note: This most likely has nothing to do with your system as I run Cinema 4D and ZBrush on a daily basis in my Windows 7 Virtual Machine with no lag whatsoever.