Reference databases & lookup services to collaborate these specifications.
Everymac.com ultimate lookup
mactracker.ca database app (download) runs on much newer Mac
Hardware cannot physically use any modern upgrade path
nor can those obsolete/antiques run newer software, either.
Do you already have install-restore DVD discs for Tiger or Leopard?
If so, that'd probably do fairly well; esp. w/ 7200-RPM HDD. I've this
installed in 2006 MacBook1.1 13-inch 'first edition' 1.83GHz coreduo
on Leopard 10.5.8 with 2GB RAM (max) & 150GB 7200-RPM drive.
If your old iMac still can go online, and runs Tiger or Leopard
then try TenFourFox browser, version G3_TenFourFox. Special
instructions, aside from their main download, page tells how.
If you upgrade/buy Snow Leopard 10.6.3 (retail disc) then get
online updates to bring it to full 10.6.8; that's as good as it gets.
Apple site has the small download to finish what's on the DVD.
(The intel-based mac only uses one version Ten4Fox_G3 browser
these otherwise are not supported; TenFourFox is all volunteer)
• Can 10.4Fx run on an Intel Mac with 10.4, 10.5 or 10.6? | github/wiki/the FAQ#
https://github.com/classilla/tenfourfox/wiki/AAATheFAQ#can-104fx-run-on-an-intel-mac-with-104-105-or-106
Use following link and cryptic instructions, above to install this:
TenFourFox for G3 processors - recent custom 'firefox/tenfourfox'
https://sourceforge.net/projects/tenfourfox/files/fpr31/TenFourFoxG3-FPR31.app.zip
• TenFourFox: A fork of Mozilla Firefox for Power Mac and Mac OS X - Tiger/Leopard PowerPC
https://www.floodgap.com/software/tenfourfox/
This browser cannot work with Lion 10.7.x ~ systems past 10.6.8, don't include 'Rosetta' on DVD.