physical memory is at 90% ?? that typically means you have a ton of processes on at a single time, For example if you have like 20 tabs open on your browser along with iTunes and other programs. You can lower your memory usage quickly by closing out of programs, also if you stop unnecessary programs from opening on startup. That should help too. Depending on how much RAM you have you should see an increase in speed. I have 4GB of RAM and when its idle I only use about 35-40% of my memory.