A FF45 for i686+ would be nice-to-have. I'm not using FF45. Installing two different FF versions is possible, packaged and installed, but there's no way to solve the disk full-errors of that route.
Test 1 (out of 4). No reply expected, I'm just reporting. YMMV. A.o. no video tests, due to a lack of relevancy. Grab a dual core machine, visit YouTube, and smile when the difference is that CPU load peaks have dropped from a honest 100% to 98%.
IBM ThinkPad 600E, Pentium II, CPU 500 MHz, RAM 224 (expected: above 256!?) MiB:
SM 2.35:
Start-up time until <Ctrl-O> menu is actually being displayed: 3'10"
CPU load: not that relevant, no improvements expected, almost anything is acceptable
SM 2.42, r3, second time to account for initial profile checks. Updated add-on, no updated langpack to save a few hours, no changes (AdBlock Plus, ChatZilla) because the CPU load is not that relevant:
Start-up time until <Ctrl-O> (file open) menu is actually being displayed: 3'34"
Stability: not relevant and not tested, doing anything may result in a Microsoft Harddisk Torture- and/or disk-full-related crash anyway.
CPU load: ~100%, responsive, may have been 2-6%'ish before the add-on update.
Works as expected, including the possible and known 100%-issue and causes.
SM 2.42, r3_O2, no changes:
Start-up time until <Ctrl-O> menu is actually being displayed: 3'12"
SM 2.42, r3_s, no changes:
Start-up time until <Ctrl-O> menu is actually being displayed: 2'19"
If results are WTF'ish weird, then swapping or other human errors may have been involved somehow...