Mac OS X 10.5.8 Reduces Drive Space Usage

I'd day this is probably a first in my career. It appears that after installing the Mac OS X 10.5.8 update my drive space requirements have gone down.

Before 10.5.8

Yup, that's right, my System partition now occupies a bit less space than it did prior to the update. I'd first noticed this on my old PowerBook and thought I was going nuts. But after installing the update on my Intel tower as well, the results seem pretty consistent.

After 10.5.8

If this is the sort of thing we can expect in Snow Leopard, you can officially call me excited.

Now about those upgrade disks. Anyone know what's up with them?

Anyone?

UPDATE:

So I just installed three additional updates — Safari 4.0.3, Security Update 2009-004, and the latest GarageBand patch — and my available drive space has increased even more. One commenter has brought up the possibility that these space gains are simply due to swap files being deleted after a reboot. But all these screen shots — including the first one — are taken immediately after a reboot, so I don't think swap files should be a factor. Also, the gains on my PowerBook were significant enough to rule out swap. And now I'm seeing subsequent updates freeing up even more drive space.

After Additional Updates

No, I think something else is going on here. My suspicion is that we're beginning to see some of the sorts of efficiency improvements — like a smaller disk space footprint — that Snow Leopard is supposed to be all about. I suspect that whatever they're doing in Snow Leopard to reduce disk usage is making its way into the latest bunch of updates, and so these updates are actually decreasing the amount of disk space required by the OS.

But this is only a wild guess. For the record, I've got no more evidence than I'm presenting here, and have not been thorough nor the least bit scientific in my approach to this phenomenon, nor do I have time to investigate much beyond these observations.

I think you have to admit, though, if nothing else, it's quite odd to see a consistent increase in drive capacity after multiple system updates. This is not the usual way of things.