[Exim] split_spool_directory overhead

Hi folks,

I'm just wondering whether split_spool_directory costs any kind of
measurable overhead on systems that don't require it.

FreeBSD 4.4-RELEASE will ship with optional UFS dirhash support, which
greatly improves the system's performance in the face of massive
directories.

I've enabled the support on my mail servers and it really makes a meal
of my large (30KB+) directories.

So does split_spool_directory cost a lot or should I just leave it
enabled in the spirit of "if it ain't broke"?

Ciao,
Sheldon.