This is all Jagex's fault, its not your laptop. Go look on RS forums under Technical Support and see all the crys of outrage from the players who are unable to play smoothly with the update yesterday.
I have a very high spec laptop, and it used to run at 40-50 FPS on RS HD beautifully, now I have less than 10 FPS and I am lagging like crazy, all after yesterdays graphical rework. I am getting tired of all these needless updates while Jagex completely ignores the thousands of players who are unable to play because of this shit!

