Now that I have the test suite working and installation is quick, I set up the software on a freshly-installed machine on my home network, ran the suite, reinstalled using InnoDB tables instead of MyISAM, ran again, installed MySQL 4.0.12, and ran again.

The semi-bad news: there didn't seem to be any difference in performance with any of these changes. The variance in timing among setups wasn't much more than the variance from one run to the next. The actual numbers are below. Probably the most important numbers are the "sec per fetch" and "sec per search" at the end--those are the timings of regular page fetches and searches done by background threads that run during the conformance tests and best simulate actual use.

The semi-good news is that MySQL 4.0.12 instaled easily and worked out of the box with no problems, and seems as reliable as its now "production" status would indicate, and didn't have any performance problems, so it seems there would be no downside to using it if we decided to upgrade to take advantage of its features.

MyISAM:

Test "Links" Succeeded (120.817 secs) Test "HTML" Succeeded (321.443 secs) Test "Editing" Succeeded (229.574 secs) Test "Parsing" Succeeded (23.135 secs) Test "Special" Succeeded (124.010 secs) Test "Search" Succeeded (33.702 secs) Test "Math" Succeeded (49.452 secs) Stopped background threads. Fetched 213 pages in 784.356 sec (3.682 sec per fetch). Performed 201 searches in 397.350 sec (1.865 sec per search). Total elapsed time: 0 hr, 16 min, 41.367 sec.

InnoDB:

Test "Links" Succeeded (113.099 secs) Test "HTML" Succeeded (247.384 secs) Test "Editing" Succeeded (175.459 secs) Test "Parsing" Succeeded (16.881 secs) Test "Special" Succeeded (159.286 secs) Test "Search" Succeeded (45.763 secs) Test "Math" Succeeded (60.805 secs) Stopped background threads. Fetched 194 pages in 721.915 sec (3.721 sec per fetch). Performed 192 searches in 343.591 sec (1.771 sec per search). Total elapsed time: 0 hr, 15 min, 20.568 sec.

MySQL 4.0.12:

Test "Links" Succeeded (114.171 secs) Test "HTML" Succeeded (258.449 secs) Test "Editing" Succeeded (212.278 secs) Test "Parsing" Succeeded (21.764 secs) Test "Special" Succeeded (131.613 secs) Test "Search" Succeeded (31.383 secs) Test "Math" Succeeded (52.241 secs) Stopped background threads. Fetched 201 pages in 748.631 sec (3.725 sec per fetch). Performed 200 searches in 350.369 sec (1.743 sec per search). Total elapsed time: 0 hr, 15 min, 51.312 sec.