Isn't this similar to what FasterFox add-on does? I had tried FasterFox for a while. The problem is it can screw up everyone else who is trying to get on... and be compounded by every other person who uses it. Imagine every person who comes on here sending 30 requests at once.
Since Fasterfox constantly requests new files, it can cause many servers to overload much faster than if a person viewing the same content without Fasterfox were to view it.
That is from an article
I came across. Fasterfox only sends half the requests of the little tweak you have pointed out.
After reading the article, I felt kind of guilty and got rid of it. I honestly had not noticed much of a difference with it and with PC's just getting faster and faster, I don't know I really need such a tweak.