I did further tests now...
The blue faces are gone away, thanks for the hint!
I tried different scenarios (always with HD4550, MPC HC 32 bit newest build, Windows7 64bit, Cyberlink Video Decoder PDVD11):
EVR Custom Renderer directly connected to Cyberlink:
With SW or HAM almost same GPU load, CPU load drops a little bit. MPC HC shows "DXVA" in bottom bar.
EVR Custom Renderer with ffdshow raw filter:
CPU and GPU load the same with SW and HAM, MPC HC shows NOT "DXVA".
madvr (my prefered renderer): no difference in GPU and CPU load, no "DXVA"
All combinations: I have to wait about 10 seconds for video playback to start, in this time RAM load of the PC rises up to 95% and then goes down to normal level and then video playback starts. No stuttering in all scenarios, playback is fine.
Perhaps HD4550 doesn´t work because it lacks power in comparison to higher grade GPUs. Or one has to tweak with DXVA Checker settings like VForceUVDxxx...
But it´s not so bad, SVP makes a great job for me, it´s much easier to work with dropdown boxes than editing Avisynth scripts...
And development is in fast progress, so things will get even better.
Always nice to see that people invest their time in creating great stuff that others can use, and that for free! Thanks a lot for your work, Chainik!