I used to have some generic cooling bad which I bought on eBay for around £15. It was pretty similar to this. It worked best when I had it at about a 35 degree angle and had the laptop aligned so that the cooling pad blew air over the laptop exhaust. This would both increase the amount of cool air that the laptop could suck in, and displace the hot air near the exhaust.

My laptop would also regularly hit 100c and then thermal throttle itself but the pad definitely allowed me to get a few more frames out before the throttling kicked in.