No, interprocess communication works very well.

But remember that a lot of applications are written by morons. A badly written application is not proof that the OS is bad. On the other hand, M$ preaches "best practices" and ships development tools that are known for producing bloated and slow applications. Alas, a lot of the tools supplied together with the OS core are written using these tools, and by developers teached to use these "best practices".

Aside from the dreaded registry and the "DLL hell" namespace polution, the OS kernel actually works quite well. But the driver model used in Windows makes it almost impossible to write a good - and fully tested - driver. This makes us constantly suffer from blue screens when a third-party protected moe driver goofs and brings the machine down.

Anyway - a new Windows release is most probably not the most secure environment to take out on a test drive. Microsoft really do love to turn on every little feature someone may have dreamed up after getting a drink too much. And they seldom seem to spend tíme doing a cross-system analysis of how the features may be abused before they add and activate them.