It was long overdue, but I finally spent some time with my G5s while on break over the new year.
I fired up my Dual Processor 2.0GHz G5 with it's heavyweight GeForce 6800 Ultra DDL and within 2 minutes of playing Doom 3, the system cut out with a cracking bang. The PSU smoked up and unfortunately took the GeForce 6800 with it. I tore the machine down to inspect and yes, the PSU is dead and the 6800 is indeed toast. Maybe it was the 6800's extra power draw at fault (as it draws over the ADC pins), so hoping it is just the PSU and GPU, and not a logic board failure.
So moving onto the next unit, I fired up the Dual Processor 1.8GHz with its GeForce FX 5200 and it booted fine and worked as expected for a few days. I was fully appreciating it's relatively "low" power requirement, and how beautiful it looked with my 17" Apple Studio Display (LCD). For a G5, the DP 1.8 is fairly lightweight, but it could still take 8GB of RAM (unlike the later DP 1.8 model).
Then intermittently at first, the DP 1.8 began to exhibit what appears to also be PSU failure. It would power off randomly during operation, then randomly during boot, then power off randomly while in the boot picker or OF. Now I can't get it to boot to the desktop at all, regardless of what medium (or OS) I try to boot from. Tried removing RAM, and expansion cards, swapping GPUs and displays (non-ADC). Even tried removing the GPU and listening for boot, but it still just clicks off after about 30 seconds into the hard drive churning as it boots up. So I have returned both of my original '03 model A1047 G5s to the shelf to try to solve another day.
This brings me to the Dual Core and Quad Core units. 12 months ago I overhauled the LCS on the Quad and have had it shelved (working great, but unused) for the most part since. The Quad has an Nvidia 7800 GT (256MB) GPU which I flashed with a ROM from Macelite many years ago, but has also had very little use. My air-cooled Dual Core 2.3GHz which got a lot of use in the past (with its top-end Quadro FX 4500 512MB GPU) has also been on the shelf after doing a logic board swap this time last year due to failed RAM slots.
Once I booted up the DC again, it started to exhibit self-diagnosed RAM slot failure, which I thought was alarming given that I just "recently" replaced the logic board in full. After much trial and error, what I actually found is the 8x 2GB DDR2 unbuffered, non-ECC DIMMs I had purchased back in 2017 have each intermittently failed (at least in the pairing arrangement I picked). They are low-profile PC4200 DIMMs, that might have cost something like $6 each shipped direct from China when I bought them. Definitely not the kind of DIMMs Apple would have approved. So I took all 8 of those cheap DIMMs and shelved those too, then divided the remaining known-good, quality 8GB fully buffered ECC DDR2 (PC2-3200E-288) which were in the QC and split it 4GB each with the DC. So both units now have the same RAM, in the same slot config, and both are rock solid (no random crashes / jet-engine take offs). I should mention that the thought came over me that the logic board swap I did last year, which I believe was due to RAM slot failure, could have actually been just RAM DIMM failure because these low-profile 4200U DIMMs were installed, and had been tested in many different configurations. I am 90% certain I did test the known-good ECC DIMMs from the Quad with that DC logic board... But then again, maybe I didn't(!)
In the process of trial and error with the QC and DC, I was also swapping around GPUs, and seemingly out of the blue, the GeForce 7800 GT, which previously would score ~9500 in OpenMark has now throttled itself and can only get an OpenMark score of ~1250. OpenGL gaming reflects the same throttled state with low FPS. It still feels zippy in the Finder and other apps with QE/CI, but as soon as it needs to go into full-power OpenGL mode it just holds back. I tried all kinds of things like PRAM reset, and swapping GPUs back around between units again, but no matter which system the 7800 is in, it still only gets ~1250. The FX 4500 in comparison rocks around ~17,000 in OpenMark regardless of being in the QC or DC, and runs Doom 3 beautifully at 2560x1440 even with FSAA.
I am not sure what has happened to the 7800 GT, but it seems like it's locked itself into a low-power state. Temp sensors are all normal, it idles around 53°C and pushes up to about 70°C under load as expected. Fan runs perfectly fine. It's just power-throttled. For reference, I repasted and replaced thermal pads a couple of years ago, and the temps prove it is thermally okay. I was even going to try reflashing the ROM with the same OEM ROM (v2152.2) but ROM Dumper proved that the onboard ROM and the downloaded ROM checksum the same bit-for-bit, so I cancelled the idea of doing the PC re-flash.
Fortunately, I still have an original passively-cooled 6600 LE GPU from the DC G5 on hand, so I shelved the 7800 GT and installed the 6600 LE. In comparison, the 6600 LE (128MB) gets around ~5,500 in OpenMark, so although it's not near as capable at the 7800 GT in good health, it is better than the state it is currently in.
Anyway, I now have the DC (w/ FX 4500) setup with a 27" WQHD display and all my mid-2000 era DAW software (Ableton Live 8, Reason 4, Pro Tools LE 7 and so on) + Adobe CS3 + loads of PowerPC software + some classic PowerPC Mac games of the era.
Then across the room (to help reduce the heat), the QC (w/ 6600 LE) is humming along with a beautiful 20" Apple Cinema Display. It runs great, although a little underpowered in the graphics department. This unit is my Power bench. I plan to try some Linux options on it. I downloaded Fienix Installer 6.0.1 and then read that Fienix is dead in the water, so might try something else. What's the current state of PPC Linux these days? The last good stable PPC Linux distro I used was Ubuntu Mate 16.04 on the DC.
Moving to the topic of running temps, I am beginning to think the QC actually pushes out far less hot air than the DC. Would anyone agree or disagree on this? I haven't run any tests to support this theory, just feels like the DC pumps out more heat than I remember it did.
Actual CPU temps are actively cooler on the QC (both CPU units cores idle at 46°C), while the DC (which is healthy) idles around 49-50°C (while on Reduced power). Fans on the DC mostly idle at lowest speeds (intake/exhaust at 500rpm), while the QC idles a bit higher (intake/exhaust at 1100rpm plus the single water pump at 1300rpm).
It's worth noting the FX 4500 (in the DC) is a bit of a power hog, so I imagine quite a bit of heat from the DC would be due to the GPU. However, the DC runs whisper quiet, hardly ever ramps up, and the QC is almost always making some form of fan and/or pump noise. So maybe it's just the way Apple tuned them – DC for near-silent operation, QC as a noisy powerhouse.
Anyway, just wanted to share some ramblings, and to say hi, I'm still here, and still enjoying these PowerPC Macs – A PB G4 12" spent the majority of 2025 on my desk, although got minimal use, it was humming along when I needed it. I have been paying special attention to Panther on the G4s these days – more on that to come.
Peace
I fired up my Dual Processor 2.0GHz G5 with it's heavyweight GeForce 6800 Ultra DDL and within 2 minutes of playing Doom 3, the system cut out with a cracking bang. The PSU smoked up and unfortunately took the GeForce 6800 with it. I tore the machine down to inspect and yes, the PSU is dead and the 6800 is indeed toast. Maybe it was the 6800's extra power draw at fault (as it draws over the ADC pins), so hoping it is just the PSU and GPU, and not a logic board failure.
So moving onto the next unit, I fired up the Dual Processor 1.8GHz with its GeForce FX 5200 and it booted fine and worked as expected for a few days. I was fully appreciating it's relatively "low" power requirement, and how beautiful it looked with my 17" Apple Studio Display (LCD). For a G5, the DP 1.8 is fairly lightweight, but it could still take 8GB of RAM (unlike the later DP 1.8 model).
Then intermittently at first, the DP 1.8 began to exhibit what appears to also be PSU failure. It would power off randomly during operation, then randomly during boot, then power off randomly while in the boot picker or OF. Now I can't get it to boot to the desktop at all, regardless of what medium (or OS) I try to boot from. Tried removing RAM, and expansion cards, swapping GPUs and displays (non-ADC). Even tried removing the GPU and listening for boot, but it still just clicks off after about 30 seconds into the hard drive churning as it boots up. So I have returned both of my original '03 model A1047 G5s to the shelf to try to solve another day.
This brings me to the Dual Core and Quad Core units. 12 months ago I overhauled the LCS on the Quad and have had it shelved (working great, but unused) for the most part since. The Quad has an Nvidia 7800 GT (256MB) GPU which I flashed with a ROM from Macelite many years ago, but has also had very little use. My air-cooled Dual Core 2.3GHz which got a lot of use in the past (with its top-end Quadro FX 4500 512MB GPU) has also been on the shelf after doing a logic board swap this time last year due to failed RAM slots.
Once I booted up the DC again, it started to exhibit self-diagnosed RAM slot failure, which I thought was alarming given that I just "recently" replaced the logic board in full. After much trial and error, what I actually found is the 8x 2GB DDR2 unbuffered, non-ECC DIMMs I had purchased back in 2017 have each intermittently failed (at least in the pairing arrangement I picked). They are low-profile PC4200 DIMMs, that might have cost something like $6 each shipped direct from China when I bought them. Definitely not the kind of DIMMs Apple would have approved. So I took all 8 of those cheap DIMMs and shelved those too, then divided the remaining known-good, quality 8GB fully buffered ECC DDR2 (PC2-3200E-288) which were in the QC and split it 4GB each with the DC. So both units now have the same RAM, in the same slot config, and both are rock solid (no random crashes / jet-engine take offs). I should mention that the thought came over me that the logic board swap I did last year, which I believe was due to RAM slot failure, could have actually been just RAM DIMM failure because these low-profile 4200U DIMMs were installed, and had been tested in many different configurations. I am 90% certain I did test the known-good ECC DIMMs from the Quad with that DC logic board... But then again, maybe I didn't(!)
In the process of trial and error with the QC and DC, I was also swapping around GPUs, and seemingly out of the blue, the GeForce 7800 GT, which previously would score ~9500 in OpenMark has now throttled itself and can only get an OpenMark score of ~1250. OpenGL gaming reflects the same throttled state with low FPS. It still feels zippy in the Finder and other apps with QE/CI, but as soon as it needs to go into full-power OpenGL mode it just holds back. I tried all kinds of things like PRAM reset, and swapping GPUs back around between units again, but no matter which system the 7800 is in, it still only gets ~1250. The FX 4500 in comparison rocks around ~17,000 in OpenMark regardless of being in the QC or DC, and runs Doom 3 beautifully at 2560x1440 even with FSAA.
I am not sure what has happened to the 7800 GT, but it seems like it's locked itself into a low-power state. Temp sensors are all normal, it idles around 53°C and pushes up to about 70°C under load as expected. Fan runs perfectly fine. It's just power-throttled. For reference, I repasted and replaced thermal pads a couple of years ago, and the temps prove it is thermally okay. I was even going to try reflashing the ROM with the same OEM ROM (v2152.2) but ROM Dumper proved that the onboard ROM and the downloaded ROM checksum the same bit-for-bit, so I cancelled the idea of doing the PC re-flash.
Fortunately, I still have an original passively-cooled 6600 LE GPU from the DC G5 on hand, so I shelved the 7800 GT and installed the 6600 LE. In comparison, the 6600 LE (128MB) gets around ~5,500 in OpenMark, so although it's not near as capable at the 7800 GT in good health, it is better than the state it is currently in.
Anyway, I now have the DC (w/ FX 4500) setup with a 27" WQHD display and all my mid-2000 era DAW software (Ableton Live 8, Reason 4, Pro Tools LE 7 and so on) + Adobe CS3 + loads of PowerPC software + some classic PowerPC Mac games of the era.
Then across the room (to help reduce the heat), the QC (w/ 6600 LE) is humming along with a beautiful 20" Apple Cinema Display. It runs great, although a little underpowered in the graphics department. This unit is my Power bench. I plan to try some Linux options on it. I downloaded Fienix Installer 6.0.1 and then read that Fienix is dead in the water, so might try something else. What's the current state of PPC Linux these days? The last good stable PPC Linux distro I used was Ubuntu Mate 16.04 on the DC.
Moving to the topic of running temps, I am beginning to think the QC actually pushes out far less hot air than the DC. Would anyone agree or disagree on this? I haven't run any tests to support this theory, just feels like the DC pumps out more heat than I remember it did.
Actual CPU temps are actively cooler on the QC (both CPU units cores idle at 46°C), while the DC (which is healthy) idles around 49-50°C (while on Reduced power). Fans on the DC mostly idle at lowest speeds (intake/exhaust at 500rpm), while the QC idles a bit higher (intake/exhaust at 1100rpm plus the single water pump at 1300rpm).
It's worth noting the FX 4500 (in the DC) is a bit of a power hog, so I imagine quite a bit of heat from the DC would be due to the GPU. However, the DC runs whisper quiet, hardly ever ramps up, and the QC is almost always making some form of fan and/or pump noise. So maybe it's just the way Apple tuned them – DC for near-silent operation, QC as a noisy powerhouse.
Anyway, just wanted to share some ramblings, and to say hi, I'm still here, and still enjoying these PowerPC Macs – A PB G4 12" spent the majority of 2025 on my desk, although got minimal use, it was humming along when I needed it. I have been paying special attention to Panther on the G4s these days – more on that to come.
Peace
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