I've been wondering the same thing. I'm migrating from 9.0 SP4 to 9.6 SP2, and building the HII driver database has turned from 3-5 minutes to 30+ minutes, for almost the identical driver setup. (Repository files - 4309 in 9.0, 4411 in 9.6.) What happened to HII to slow it down so much?
Just as an example of what I mean. I removed a driver package and updated two others. Clicked Build at 11:38, the progress bar hit the end at 11:57. It's now 13:27 and it's *still* sitting there thinking... Since rebuilding the HII drivers occupies the entire console (rather than being a background task) I can't do anything else in the meantime.