My 7 year old PC can run 3 flash heavy pages concurrently and never go beyond 70% CPU and I was intentionally trying to stress test it. Buy some dang memory for your computer.

Your choppy video is probably due to your lack of due diligence in good codecs, drivers and players. (i.e. user error). It has next to nothing to do with flash. Stop trying to make up things to blame on flash.