Very low fps

I try edit my videos in Blender. In real this is more hard then in my current video editor. But I have idea completly switch to Linux in future and do all my work in Blender. I have MTS files with 50fps. When I apply some effects to track and click play to preview - my video run is to slow in preview window - aboute 17-18fps sometimes 9fps. I have i7 4 core CPU 8 MB RAM computer. Can I fix this?
Thank you!

Yes it can be fixed .Video editors have ‘proxy’ which is a lower resolution film strip

Thank you.