Q: OSX 10.4 on eMac?

Hi Greg, & a warm welome to the forums & Macdom!

Any eMac can run 10.4.x or 10.5.x even if it has enough RAM.

Tiger Requirements...

To use Mac OS X 10.4 Tiger, your Macintosh needs:

    * A PowerPC G3, G4, or G5 processor

    * Built-in FireWire

    * At least 256 MB of RAM (I recommend 1GB minimum)

    * DVD drive (DVD-ROM), Combo (CD-RW/DVD-ROM) or SuperDrive (DVD-R) for installation

    * At least 3 GB of free disk space; 4 GB if you install the XCode 2 Developer Tools  (I recommend 20GB minimum)

http://support.apple.com/kb/HT1514

See Tom's, (Texas Mac Man), great info on where/how to find/get Tiger...

https://discussions.apple.com/message/15305521#15305521

Or Ali Brown's great info on where/how to find/get Tiger...

http://discussions.apple.com/thread.jspa?messageID=10381710#10381710

Leopard requirements/10.5.x...

    *  Mac computer with an Intel, PowerPC G5, or PowerPC G4 (867MHz or faster) processor

minimum system requirements

    * 512MB of memory (I say 1.5GB for PPC at least, 2-3GB minimum for IntelMacs)

    * DVD drive for installation

    * 9GB of available disk space (I say 30GB at least)

Trouble is Apple no longer sells it, check eBay & such for the Retail version, not the Gray Discs...

http://www.ebay.com/sch/i.html?_nkw=mac+os+x+leopard+retail+10.5

There are workarounds if the 867MHz is the only hangup...

http://sourceforge.net/projects/leopardassist/

http://lowendmac.com/osx/leopard/unsupported.html

Here's a page with the specs for all eMacs http://www.everymac.com/systems/apple/emac/index-emac.html All are identified as A1002. For information on your Mac (model, date of production, etc) then enter your serial number at this site. Information, based on the serial number, will be shown.  http://www.chipmunk.nl/klantenservice/applemodel.html or last 3 characters of S/N at this site http://www.everymac.com/ultimate-mac-lookup/ Post back what model you have.

Don't buy a gray colored installer even if the description says for eMac. Unless you have the 1.42GHz model that came with Tiger preinstalled. Because the operating system will be older than Tiger 10.4 on the other eMacs. Gray installers are generally model specific & won't work on a different model.

 Cheers, Tom

That's great on the eMac but realize that you were given pretty old computer  - kind of like if somebody gave you a 10 year old PC running XP nowadays, except MS operating systems seem to be supported a lot longer than Mac operating systems.  Anyway, getting hold of Tiger or Leopard will be tricky, and maybe costly, and with both systems you're using a computer and software that is no longer supported by Apple (welcome to the gang).  Maany of us still run them, but it's a bit of an art at times. I'm just letting you know not to expect blazingly fast performance and you'll have to learn tricks and workarounds.

Texas Mac Man, Leopard (and Tiger) disc sources - https://discussions.apple.com/thread/3636662

"a brody" post about upgrading to Leopard - https://discussions.apple.com/thread/3373795

Once you figure out which exact model you have based on the specs and serial number, you may be able to find the right discs for your machine. You can indeed buy Apple gray discs with confidence, as long as you know they'll work on your specific system (those discs also workk on a wide variety of other systems).

But if you choose to go the retail disc route, just know it won't necessarily be cheap. You can find them on eBay, but they're almost always selling for the original retail price or higher; you can try Craigslist too, but make sure it's the right item before you buy it, and always deal locally if you can.