Export in Premiere CS6 is very slow, but why?

Hello,

I work with a

Intel i7 3770k @ 3.5 GHz

16GB RAM

GeForce GTX 560 TI

2TB RAID-0

In this project I did the color correction via After Effects and replaced the clips in the Premiere Pro timeline with AE Compositions after I edited them.

Now when exporting it takes about 2,5 hours for a 12 minute video. The cpu only works on 22% and the ram on 35-40%

That never happened before. A 12 min video took about 30 minutes to export and the cpu was at 100%. Why not now? Is that because of the links to the AE Compositions as it's the first time I work with these?

How can I provide more cpu power to the exporting process?

Thanks for any help.