CPU performance rises when I'm opening an other application/dialog

Hi!

My application with a direct3d device needs only about 01 - 02% of
cpu performance, but if I call a dialoge from the same application
the cpu performance rises up to 50%.
This happens also, when I'm opening an other application like
fireworks or something at the same time...
I'm rendering the Data in the OnPaint - Event...

Thanks Willi
.

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