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That page (last updated with MorphOS 3.16 release in March 2022) is out of date since MorphOS 3.18 release in May 2023 which added official support for both iMac G5 iSight models.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

@ ppc-grinch - I have had, and am still having, no-end of trouble with v3.20 of MorphOS with my iMac A1145 iSight, which also has the X600 GFX chip on the logicboard. In fact I am fairly sure that a lot of the internal components will be very similar, if not the same, other than the smaller screen and probably the screen inverter is likely a different model. The main problem for me is that it refuses to go online with v3.20 as a standard ISO installation, but with a few tweaks and changes, sometimes reverting to the netconfig.library off the v3.18 ISO, at the suggestion of jacadcaps, there have been some degree of more usability, who seems to have made similar suggestions to other hardware users that have installed v3.20 and found themselves unable to get their networks working/recognised. The one more limiting factor seems to be that the Preferences GUI when you swap some of the network settings then goes inactive, and you then need to reboot, and you may not even have had any success getting online during those attempts to do so.

I have not had any GFX chip issues with my A1145, but it seems that this v3.20 may have got more significant issues that need fixing than any other version that was previously released, just my observation of discussions on this forum.

I have spoken with jacadcaps and still need to get back to him with more details about using it with my ethernet connection. He too has an A1145 iMac, so that is good for us to be, basically, on the same hardware to compare what works and what seems to be at conflict with the latest v3.20 operating system. At least that is the way it is with my system - conflicts with the OS.

I can install v3.20, but be aware that if you do get it installed OK, that the ogg.demuxer is Toxic/Broken and you need to disable, isolate, or delete it from the MOSSYS: Classes/ Multimedia until it is fixed, probably in v3.21 which for me, cannot be released soon enough ... once the issues that are affecting the iMac have been resolved completely.

If I was you, I would download both the v3.18 and v3.19 ISOs and re-install with v3.18 first of all and see how that works for you, bear in mind that the most recent version of Wayfarer you can use IIRC is v8.5 with v3.18 of MorphOS. With v3.19 the lastest version is v11.2, but I would advise you to try to install v3.18 first of all, and report back here your findings. If all goes OK with v3.18 then install v3.19 and then report back here with your results.

I hope this information is useful to you, especially as you have similar hardware to mine, though your GFX issues have not troubled me as yet, and I hope that they don't, but I hope that yours get resolved quickly.

I am currently running MorphOS on my iMac from the v3.19 MorphOSboot CD (registered - no timeout) sometimes from v8.5 Wayfarer, as I have advised you to try. I am not sure that there is not a problem with the Preferences GUI in v3.19's ISO, as I have described briefly above, but as you will work out, if I am using v3.19 though I can also use the v11.2 Wayfarer as well, which I am doing right now.

I feel sure that the problems we are facing currently with v3.20, well some of us at least, will be supported by the MorphOS Development Team to, hopefully soon, deliver a stable fully working version of MorphOS that we can all enjoy as we usually do.

I've made some more rudimentary observations just today after fiddling with this iMac after a little over a week since this thread began. Life was in the way this week. I have yet to try the recommendation given by NewSense. It seems like something I may have to do, but I would hope not, since that would mean continuing to use MorphOS 3.19 until 3.21 comes out.

My new observation:
These graphics issues appear exacerbated upon reboots, or maybe even caused by them. Using the iMac intermittently sees no such graphical mayhem. Rebooting just once spawns the issues and each successive reboot arrives me at the psychedelic trip that I described in the first post. This explains why I saw no graphical issues when using the MorphOS 3.20 burned CD because the iMac had no need to reboot until after the installation completed, to which the graphical issues appeared. This means that there isn't any difference between the installed MorphOS and the MorphOS CD environment when reproducing this bug.

It crossed my mind that this could be a heat-related issue with the GPU? But I used the Temps module in the Screenbar to monitor temperatures. Before the first reboot today, I observed temperatures hovering around 50 degrees C (122 degrees F). After the first reboot, the temperatures hovered around 55 degrees C (131 degrees F). That increase in temperature is negligible! After the second reboot, the temperature spiked to about 65 degrees C (149 degrees F). That's getting toasty, but still perfectly manageable. After a few seconds, the temperature easily settled to about 57 C. This doesn't strike me as catastrophic failure temperatures, so I ruled out the possibility that these graphical bugs are a heat-related issue.

I just turned on my iMac now (it's been about twenty minutes) and the graphical issues came again after 40 or so seconds. The temps module in the Screenbar reports 47.4 degrees C, so it's not heat-related at all. Opening the Thermals program specifically reports the Radeon GPU's temperature as 41 degrees C and the CPU is idling at 2% usage.

Current assessment:
This bug appears to be reproducible by reboots. However long the iMac must be turned off before using MorphOS 3.20 again is unknown, but apparently it must be over 20 minutes, at least. But after that time lapses, I am able to use the iMac for as long as I am allowed to by the MorphOS 30 minute time limit, at least as far as I can determine. There could be something else as an unknown variable that contributes to this.

Overheating is not a factor in replicating this graphical glitch.

I am likely to try out NewSense's solution next.

Could you post a photo of the screen when the issue manifests?

MorphOS 3.19:
I am displeased to announce that the same issues occurred in MorphOS 3.19, so this is not specific to MorphOS 3.20, meaning that this is either a long-standing issue with ATi Radeon X600 Pro drivers for as long as MorphOS has had them or this is specific to my particular iMac. I would be one unlucky fella if my iMac is ready to die after I installed MorphOS to it. I hadn't used it since earlier this year and it didn't experience these graphical issues.

More Testing:
After writing off this possibility, I reconsidered the chance that this may be a heat-related issue to be sure. I believe I was wrong, and at the end of this new test I am increasingly of the opinion that heat may be an underlying factor.

I adjusted the fan speed from within MorphOS Preferences program and observed the Thermals program report temperatures. Despite it reporting that the “CPU/GPU Fan” spinning at 5700rpm, both the CPU and GPU temperatures remained where they were at; 59 C and 74 C.

If the problem were specific to MorphOS in general, I also booted into OpenFirmware to prove it. Display bugs or graphical glitches were not present in OpenFirmware. Interesting. I'm not sure if doing this is applicable, but I do know that the PowerMac G5 requires the default factory GPU in the 16x slot on the motherboard to access OpenFirmware, so I thought that this might shine light on to any potential GPU failure. To be certain, I could have installed Mac OS X and rebooted a few times to see if the same issues occur in Mac OS X, but this was quicker. I may reinstall Mac OS X in an attempt to recreate this issue if push comes to shove, regardless, if this issue is particular to my iMac's GPU.

I reset the NVRAM after this. I’m not sure if this was applicable, either. I don't think the NVRAM affects anything GPU-related, but I did this anyways. After NVRAM reset, the Mac reboots itself automatically. No graphical glitches present within MorphOS yet. GPU temp is at 60 C now, slowly increasing. Teetering between 64 and 65 C after a few minutes. I increase the fan speed using MorphOS Preferences program's “iMac” section by cranking the slider next to “Keep CPU & GPU below”, as before. Temps reports that “CPU/GPU fan” is steadily increasing to 2500rpm as a result of my change. GPU temp stabilizes to 63 C, going down to 62 C. After a few minutes, fan rpm speed increases to 3800rpm and GPU temp sits at 62 C, unchanging. At this time I use the Morphever demo to benchmark the GPU and attempt to recreate the graphical failures. Catastrophic glitches return during the Morphever demo, rendering iMac inoperable and unresponsive to keyboard input. I am reconsidering that it is a temperature-related issue now that the issue is not only reproducible, but now able to be summoned with a graphically demanding software like Morphever. It isn’t just a “reboot” problem, but that the temperatures rose considerably with each consecutive reboot that caused the GPU to bug out. After rebooting, Temps reported that the GPU temperature is at 59 C, which is lower than it was before it bugged out playing Morphever, though. North Bridge temp became considerably higher after a reboot, now sitting at 74 C. It was less than 50 C beforehand. With the GPU sitting at 59 C, the catastrophic glitches returned after about 15 minutes, unprompted.

I found something interesting when navigating through MorphOS Preferences. Under the “Monitors” section, if I select one of the Mode Lists and select “Edit”, then “Test”, the test actually reproduces the graphical effects that I describe happening. Everything has been left at their default settings.

New current assessment:
1. OpenFirmware displays no graphical glitches, no matter the GPU temperature
2. Issue is reproducible after 2 or more reboots, which increases GPU temperature
3. Issue is reproducible while running a GPU-dependent software like Morphever, which increases GPU temperature
4. Issue starts small and gradually becomes more severe until Mac locks up within 15 minutes
5. Based on these experiences, glitches may occur once GPU temperature is at least 59 degrees Celsius, but the glitches are not immediate
6. GPU Temps above 59 C do not produce any different sort of effects; effects gradually worsen whether GPU temp is at 59 C or way above 59 C, meaning that there is some threshold or tolerance before everything degrades
7. My earlier comment that waiting over 20 minutes before turning on the iMac after turning it off may now be explained with the fact that the GPU has not yet cooled off to a temperature that doesn't produce these graphical bugs; a cold boot shows the GPU temp around 40 C, according to Temps in MorphOS

Quote:

Here is a link to six photos depicting the graphical results: https://postimg.cc/gallery/sBcjZPH. The link is set to expire in 7 days. JavaScript is not required to view the images. Three photos are general examples of the results, one photo is of it occurring as Morphever is running (presumably any program taxing on the GPU will produce these results without fail as well but I just chose what came to to mind), one photo is of what I eventually see once the glitches first appear, and one photo is of MorphOS Preferences in the Monitors section where a recreation of the effects may be summonable upon clicking "Test".