Benefits of installing swap and /usr/obj/ on seperate disks?

I've added another hard disk to my collection, and I'd like to know if there is any advantage to using some of the smaller disks for special purposes. The two roles that I have in mind are swap space and /usr/obj/.

The setup I was thinking of is:
1) IDE 1, master (2GB)
1GB swap space

2) IDE 1, slave (8GB)
/usr/obj/

3) IDE 0, master (20GB)
256MG swap space
pretty much everything else (PMET)

Putting PMET and swap as the masters on seperate channels should make swapping more efficient. This is important to me as I'm trying to squeeze every last bit from my P200, 64MB RAM system. Once opera, evolution and a few JVMs are running, things tend to bog down pretty quickly. Note that the 2GB drive is the oldest, so I have some swap on the 20GB in case it craps out.

I also remember reading somewhere that buildworld is more IO than CPU intensive, so writing to /usr/obj/ on a seperate disk should improve build times significantly.

Does this sound like a sensible, and worthwhile approach? Or am I displaying a painful ignorance of the IDE bus?

If you are only concern about speed, then yes.
BTW why would you want your /usr/obj to have 8GB? It could be way below 1GB.

What other aspects might I be concerned about? Are there any downsides to this approach? I know that nothing comes free, but I got the impression that this could have some noticable performance benefits.

I wasn't going to use the whole 8GB. As you say, one GB should be plenty. I had considered putting it on the other half of the 2GB disk, but I assumed buildworld is fairly swap intensive.

Although I didn't mention it, I had planned on eventually putting some of the /var/ partitions on the 8GB as well to see if that helps things i.e. /var/db/.

I really only use the box for development, surfing and email. It doesn't need to serve anything (except during occasional load testing when I shut everything else down). So, normal use swap speed is most important to me.

You can benefit from it only if you buildworld 24/7 but it's not practical. Why should the time buildworld takes being that important when it's merely a task you'd perform every few months?
As far as your idea on /var/db, which makes more sense only if you use databases regularly.
Now have a look at this thread.

I like FreeBSD, but not that much

I had a look at that one, but it seemed more about where /tmp/ should be mounted. I'm more interested in experiences with physical disks.

Anyway, thanks for encouraging me not to stress about it too much. I realise that whatever gains exist may be slim. I might just play around a bit, and if anything interesting happens, I'll post some info. You know, for posterity.