Windows 7 + Quicktime rendering in AE CS6

Hey Guys

just switched from a macPro to a Windows Workstation specs are:

Windows7 with ServicePack1

intel Corei7 3970X

64GB RAM

Nividia GeForce GTX680

Using Quicktime Version 7.7.4

so everything runs smoothly till i try Rendering my comp in a .mov-Container Codec doesn't matter which one i take. Tried everything from Fotojpeg to DNXHD to png. Nothing Changes. As soon as i swiitch to avi rendering it's really fast. (Project rendered in 5mins whereas i cancelled the rendering after 15mins when trying to render to QT-Fotojpeg)

I can't find any solution to this, anybody here have an idea?

Thanks for the help.