Newer is not always better

I have a test PC, with a 10+ yr old motherboard in it that I'm using for testing purposes only, just to see how much use I can actually get out of an old PC. It was built before the days of the Bad Chinese Capacitors, so it's still in like new condition.
It even runs Windows 7 Pro very well. (32bit, of course)

It has a pretty fast 500GB SATA hard drive and 2GB of DDR ram, but it's still no barn burner.
For most things it works just great. (I'm not a gamer!)

So, I installed Firefox 38.0.1 on it and BOY was it ever slow!!! I tried my normal speed-up tweaks
to Firefox to no avail.
I.E. was nice and quick, but I don't normally use I.E........ so what to do?

I went back into my archives and found Firefox 28 from almost a year ago. I installed that
and VOILA, it was just as quick as I.E.

So now I know, , , when installing Firefox on an old/slow PC, using ver. 28 is the ticket.
(then turn OFF auto updates for Firefox)

Newer is not always better!

TechnoMage

Here, here! Agreed! I run older FF 33-36 versions for now. I don't know why I have troubles with the newest, I simply rollback and stay awhile.

I'm running FF 38.05 on my system and it doesn't seem slow to me.