Kdenlive eating lots of ram

I have loaded an about 50 Full HD footage and converted it to proxy format. After loading some of the clips on to timeline, kdenlive hogs up memory upto 2 GB. I am just doing simple edit, and the proxy footage are in mjpeg format. Has anybody encountered this problem? I am using latest version of kdenlive from sunab ppa.
OS: Ubuntu 12.04 64bit.

Forums:

Have a look at this thread. Actually, at this moment, it's still in the list on the left.

Cheers

http://www.kdenlive.org/forum/memory-problems

reported bug in mantis