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Modern
24" iMac, 2.33Ghz, OSX SL

17" iMac, 2.16Ghz, OSX SL
Old School
SE/30 68030@50Mhz, OS 7.6

IIci PPC@100Mhz, OS 8.1
I thought your "Old School" computers are interesting.
They don't exist!
(one possible exception with the Iici Logic Board to Upgrade Quadra 700 and PPC 601 @100MHz upgrade, or rarely, waited for the PPC 601 @100MHz upgrade)
The SE/30 was a bad ass computer to anyone who got used to the original SE (or any "Classic Macintosh"). It had the 68030 chip that ran on the Macintosh Iix (and up) computers. Unfortunately, the SE/30 was only a 16 MHz Machine. Though you could upgrade it with a very expensive 33 MHz 68030 (same CPU type) with the "Allegro SE/30". The last supported OS on the SE/30 was 7.5.5. Mac OS 7.6 required a 32-bit "clean" ROMs. (Though I'm not sure, but maybe you could run 7.6 on it if you could run MODE32 within it? It's been too long!). There was actually an third party, 68040 "'040" upgrade to the SE/30, but even the 50MHz version of the 68040 was cancelled because it exceeded the thermal design envelope. (Let me know if you actually over clocked a 68030 to 50MHz! I would be
amazed!)
The Macintosh Iici was also the very first 32-bit "clean" Macintosh II computer. Though, unfortunately is was simply that, a first 32-bit "clean" computer meaning a 68k (68030) computer, NOT a PPC@100MHz. And it ran only @25 MHz! Though, again you could upgrade it to a bad ass 68040 running @40 MHz! It started with Mac OS 6.0.4, and could actually run all they way to Mac OS 7.6.1 (not 8.1, at least not supported, and back then, I don't remember ever trying a hack to do that, 8.1 was mostly for PPC computers anyway, though it could run on some newer, less old, 68k machines.)
Now, that exception I was mentioned above, you can change that Macintosh Iici into essentially a totally different computer, the Quadra 700 with a new Logic Board all together,
then Upgrade that with a PPC 601 @100MHz. But, WOW, that's two very expensive upgrades in one case! That "Iici" with a Quadra 700 logic board can run Mac OS 8.1. But if you upgraded it to a PPC 601 @100MHz, why not run Mac OS 9.1? Also, if you waited around 6 years, I suppose you could have waited for the PPC 601 @100MHz upgrade for your Iici. But that's quite a long time!
Your newer iMacs do exist, and could run Lion now if you upgrade them to 2 GB of the old PC2-5300 DDR2 RAM. I have the worlds first Core 2 Duo Mac Book Pro, introduced a month later than both of your iMacs. I'm running Lion with no problems, actually better than I expected, especially since it still boots into 32-bit kernel by default anyway on most 64-EFI Macs as well.