I have discovered that Editor reacts very slowly after few hours of work.
Rendering of typed text is lagged and IntelliSense also reacts much more slowly.
It's even worse than VS 2010, where this problem was expected after longer period of work.
We are working on the solution with about 50 projects.
It's possible, that problem occurs when there are many tabs opened.
The workaroud is restart of the devenv.exe.
We use Productivity Power Tools.
Guys from my team have the same problem on Windows 8.
We have the same machines:
Intel Core i5-2400 CPU @ 3.10Ghz
8 GB of RAM
64-bit Operating System
ATI Radeon HD 5450