[motvbi]

Assuming you have ruled out Chrome and Opera, what exactly do you mean by "lightest"?

[mohsen]

well to be honest i didn't give opera a chance.

by light, i really meant fast, guess a bad choice of words on my part, i really just want something really fast, not even chrome seems fast enough to me.

[GHFigs]

Give Opera a chance. It's feels light/fast enough that I use it happily every day on a laptop almost a decade old and the keyboard shortcuts are fully configurable.