That line below your signature is somewhat enigmatic:

It's an automatic appending of a collection of random snippets from the body of the post. It happens quite often when I post here. I try to remember to check for them and remove them; but sometimes I forget.

I'm told (by the PMDevs) that it is due to the browser I use -- Opera -- but the fact that it never happens on any other site I use makes me think it is more to do with PM than Opera; but its always easier to blame someone else's tools than fix your own code.

more than double time for lookup? Why? Is it due to method call/XS overhead?

I would assume so. Any XS code is always going to be at a disadvantage compared to built-ins; that's inevitable. Which means you really have to parr everything down to even begin to compete.