Comment 9 for bug 136632

In my ppa you can find updated packages, even though due to version numbers you will have to install using dpkg from command line. Packages are here:

http://ppa.launchpad.net/vincenzo-ml/ubuntu/pool/universe/l/lyx/

Don't expect them to be much faster, because there is also a bug, however if you paste some text (which seems to be a workaround for this bug) when you open a document you should notice a much better responsiveness when editing and moving cursor than with assertions on, after the same workaround.