VideoStudio :: X4 / Considerable Quality Loss At Rendering AVCHD-footage?

I am confronted with a considerably quality loss when I edited and rendered the material from my Sony HDR-CX130 camcorder. It shoots *.m2ts 1920x1080 at 50i (this is in fact 25 fps, I assume).

The loss is visible when there are moving objects or when the camera moves: very not-fluent and not-smooth movement-representation, while the original footage playbacks fine and smoothly in any mediaplayer (Sony PMB or Windows Mediaplayer).

As if the rendered material has a framerate of 12 fps! Which isn't the case, in fact.

I did some experiments: render to other formats like MPEG, tried it on the laptop of a friend who also has CVS X4 installed (W7 SP1, i5 2,3GHz, 4GB RAM),I used properties of first videoclip (which actually doesn't happen), set camcorder at 50p; all without better results.

Project properties I use in CVS X4:

PAL (25 fps)
Microsoft AVI-files
8 bit, 1920 x 1080, 25 fps
Frame-based
Microsoft Video 1

This I was told here to use in order to get stills that are also 1920 x 1080 in size.[URL]

Is the un-fluent playback of edited AVCHD normal, will it be better in version X6?This is visible when playing back the rendered footage in Sony PMB and WMplayer as well.