So I remember when I had Snow Leopard I could simply switch to clamshell mode and open the lid. That improved the wifi speeds of course. But then Lion came along and stopped that from being possible. Instead the screen forced on without using a magnet to stop it. I didn't have a magnet so i tried something else: changing the position of the macbook. This might sound silly and lots of people have probably discovered this before me but i will post what i found anyway. I tried first to make the back face the direction my router was in, but the result wasn't amazing. Then I placed the macbook on its side upright so the lid was in technically an 'opened' angle. The result was ok for about a minute then things dropped again. So i got stupid and placed it upside-down with the back facing the router, and the speeds increased to about 80% of their full capacity. I thought that was really good so I placed it at 90 degree angle with the screen at an 'open' angle with the underneath facing the router direction, apple logo pointing away from the router direction. Speeds about 90-95% the full capacity which I think is a good achievement. Hopefully this might help out other clamshell users as well.