I'm not sure this has been posted here before or not but ......take a look at this...it's running on my laptop right now and it doesn't effect processing speed at all.
http://www.bbc.co.uk/sn/hottopics/climatechange/aboutexperiment1.shtml
http://www.bbc.co.uk/sn/hottopics/climatechange/aboutexperiment1.shtml