I installed MorphOS 3.20 to my iMac G5 iSight (17-inch, NOT 20-inch). The CD I burned booted and went through the installation process. I’m surprised by the amount of people that don’t have the smaller 17-inch model. I scoured the internet to look through forums (including this one), and the 17-inch is rarely mentioned. To this day, I haven’t encountered a single image online of the 17-inch iMac G5 running MorphOS.

Well, I am in possession of one. So, I decided to find out for myself if MorphOS worked on it. Apparently, it’s reported rather obscurely that the 17-inch is unofficially supported since MorphOS version 3.16. Morph.zone's library reports that the 20-inch iMac iSight is an “unofficially supported machine since 3.12” and the 17-inch iMac iSight is an “unofficially supported machine since 3.16”. Well… the MorphOS 3.20 installer worked on mine worked, so I ejected the disc and booted into the installed operating system, but the graphics are wonky. I can only describe them as psychedelic television static, which is strange because the graphics were fine during the installer from the CD.

I rebooted my iMac and the graphics were seemingly back to normal, although sometimes the graphics would “jiggle”, warp, glitch, or however I could put it. I went into MorphOS Preferences program and changed the Screens color depth from 24-bit to 16-bit, but that didn’t fix anything. Eventually my display reverted back to psychedelic garble and my mouse ceased to function, then the fans ramped up to maximum. I had to shut down the computer manually.

The verdict is that the 17-inch iMac G5, otherwise known as the PowerMac 12,1 model A1144, is not usable with MorphOS. The speakers work, peripherals work, MorphOS is able to install to the iMac, and all of the hardware is detected by MorphOS. The GPU, the ATi Radeon X600 Pro, is apparently the only limiting factor in getting MorphOS to run successfully on this iMac. The 20-inch variant has the ATi Radeon X600 XT. The two GPUs are similar in name but in the suffix; Pro vs XT. MorphOS's official website lists the ATi Radeon X600 XT as a supported GPU, not the X600 Pro

These are my findings on attempting to install MorphOS on the 17-inch iMac G5 Model A1144.

> Morph.zone's library reports that the 20-inch iMac iSight is an
> “unofficially supported machine since 3.12” and the 17-inch iMac iSight
> is an “unofficially supported machine since 3.16”.

That page (last updated with MorphOS 3.16 release in March 2022) is out of date since MorphOS 3.18 release in May 2023 which added official support for both iMac G5 iSight models.

> MorphOS's official website lists the ATi Radeon X600 XT
> as a supported GPU, not the X600 Pro

I doubt this is the reason for your bad experience. After all, the 17-inch model is officially supported (see above). So the actual machine(s) the MorphOS developers or beta testers had at their disposal to declare that model as officially supported must have had the same GPU as yours.