If you're throwing, performance isn't the concern. You just want to clean up, return your 500 or what not, and get back to a sane state.

You already take a page fault with DWARF exceptions, since the unwind / LSDA info is probably on a different page from any of your code, as well as the personality routine itself.

that potentially happen even with normal if based error handing. If the compiler thinks the error handling path is unlikely to be run, it can move it to a cold page.