WARNING - August .NET Updates

Yesterday I installed the August patches from Microsoft onto my 64-bit Windows 7 Ultimate system, including the following three patches:

KB2539636 - Security Update for Microsoft .NET Framework 4 ...
KB2468871 - Update for Microsoft .NET Framework 4 ...
KB2533523 - Update for Microsoft .NET Framework 4 ...

This morning while doing some C-Sharp development in Visual Studio 2008 I discovered that it suddenly took several seconds to start up my programs, whereas previously they started instantly. Suspecting the .NET Framework updates, I used System Restore to roll my system back to the point before these patches were installed, and startup times are again instant.

A quick Google search turned up someone complaining about startup times with Paint.Net after installing these patches. The advice to him was that the compilation cache needed to be refreshed, but this is not the case because the programs I'm developing are freshly compiled so there's never been a cached compilation of them.

So this is a warning that you may experience slow start times for .NET programs after installing these patches.
 
With the September round of patches these two have been re-issued, and they caused the same problem again for me:

KB2468871 - Update for Microsoft .NET Framework 4 ...
KB2533523 - Update for Microsoft .NET Framework 4 ...

It might be just one of the two causing the slow startup of .Net programs, but I don't have the patience to keep installing and rolling back these updates to distinguish between them.