I had racket 5 running fine on an atom based eee pc. The most important thing is to turn off unused 'tools'. you can also restrict memory use by DrRacket. These

I had racket 5 running fine on an atom based eee pc. The most important thing is to turn off unused 'tools'. you can also restrict memory use by DrRacket. These days Minimal Racket does all the for you.