Hi, first to say - really great video editing software.
The question - I'm using a Samsung hmx-h220 (h200) camera, shooting at HD 720p, 50fps. The machine with Ubuntu and Kdenlive is Lenovo 3000N200 - not a slow one, 2GB RAM, Dual Core 1,6GHz, Video card with 512MB Ram.

Is there a way to use lower resolution in project monitor(clip monitor), because it can't render HD clips normally, and at times - not even showing the clip, only sound. I guess the machine is too slow. At the moment I'm making videos blindly, as I can't see what I edit. Other programs for Win have that option - is it available in Kdenlive. I searched the menus and couldn't find such an option, and if there isn't one, is there any way to make things better.

Thanks in advance.

You want proxy clips, which will come with the 0.8 release.