I just found and bought a dual 1.42GHz G4 CPU board that was removed from a FW800 MDD G4 PowerMac. I got it for $50 with free shipping, but without the copper heatsink. Has anyone else made this upgrade?

What things do I need to look out for in making this swap of CPU boards, if any?

I decided that I wanted to get a little extra speed and the 1.42GHz CPUs overclocked to 1.67GHz while keeping the L3 cache would probably be the best choice, instead of the 1.8GHz, or 2.0GHz third party CPU boards for the MDD model G4 PowerMacs, which are almost impossible to find and very expensive to buy.

The only Apple copper heatsinks for the 1.42GHz G4 I can currently find are on eBay for $49.95, so I will probably wait to see if I can find one cheaper and see how well the aluminum heatsink I already have will do at cooling the dual 1.42GHz cpu card, now that I have a non-stock, quieter fan in my G4 PowerMac MDD. The fan I found has good airflow, but not quite as high as the stock fan at full speed.



[ Edited by amigadave 27.10.2011 - 21:33 ]

> 2.0GHz third party CPU boards for the MDD model G4 PowerMacs

...do not exist.

https://morph.zone/modules/newbb_plus/viewtopic.php?forum=11&topic_id=7372&start=9
https://morph.zone/modules/newbb_plus/viewtopic.php?forum=14&topic_id=5875&start=218

Hi,
You are right I think the aluminium heatsink will be enough but you should add two 60x60 fan behind the heatsink. because dual powerpc cards are very hot !
For me the best choice is the 1.25 single cpu card overclocked to 1.5. You have the same caches and cpu is cold even if overclocked. (morphos only use one cpu). I did not try but I think it could be overclocked à 1.67 in changing cpu voltage but then the cpu will be hoter.

Peg4a

i have two mdds overclocked from 1.25 to 1.42. Both work without problems

peg4a,
Quote:

I believe L3 cache on the single cpu cards is only 1MB rather than 2MB. Still a good card for MorphOS use.

I had two single 1.25GHz G4 PowerMac systems, but sold them and kept only one of the dual 1.25GHz G4 PowerMac systems for myself. Maybe I should have kept one of the single G4 systems instead. I think I read somewhere that the 1.42GHz G4 PowerMacs were only made with dual G4's.

The dual G4's are better for dual, or triple booting to run MacOSX and/or Linux, but having a single G4 for MorphOS alone that runs cooler and quieter is not a bad idea.

Hyperion says they will have dual CPU support in the future of OS4, so I am sure if they can support 2 CPU's, the MorphOS Developers will be able to do the same at some point in the future too. (I know, bad joke)

I think you'll find that the 1.42 Ghz processor card will overclock better with the copper heatsink.

However, if you want to run at the standard speed, the stock 1.25 cooler ought to be adequate.

It´s very important you have 167 MHz Bus for Dual 1,42 GHz CPU-Board.

I was thinking: for just MorphOS use which is the absolute faster/most overclockable MDD? A single CPU 1,25Ghzor Double CPU ,42 Ghz?

About the L3 cache someone told that the single cpu ones has 1MB, this should not be true, the L3 cache is still 2MB. Also the bus is always 167Mhz on MDD Macs, even on single CPU ones.

[ Edited by Miky060 29.10.2011 - 11:07 ]

> the bus is always 167Mhz on MDD Macs, even on single CPU ones.

There're also MDD models with 133 MHz bus:

http://www.everymac.com/systems/apple/powermac_g4/stats/powermac_g4_867_dp_mdd.html (dual CPU, 1 MiB L3 cache)
http://www.everymac.com/systems/apple/powermac_g4/stats/powermac_g4_1.0_mdd.html (single CPU, 1 MiB L3 cache)

Yeah you're right, but in my mind there are only 1,25Ghz versions or more..

Ruud,
Quote:

PowerMac G4 FW800 dual G4@1420 has 2Mb cache L3 for CPU, and PowerMac G4 MDD dual G4@1250 has 2Mb cache L3 for CPU, other models MDD/FW800 have 1Mb calche L3 for CPU

regards

Dinivity there is the SINGLE CPU 1250Mhz that has 2MB of L3 cache:

http://www.everymac.com/systems/apple/powermac_g4/stats/powermac_g4_1.25_mdd.html

Miky060,
Quote:

no, the MDD 2003 (OS9.x capable) with single G4@1250 has 1Mb cache L3 and double G4@1250 has 2Mb cache L3 for CPU

>There're also MDD models with 133 MHz bus

Can't that be modified by a Open firmware command (unlike earlier Powermacs)?

>> There're also MDD models with 133 MHz bus

> Can't that be modified by a Open firmware command (unlike earlier Powermacs)?

According to http://forums.macrumors.com/showpost.php?p=167183 that should be possible. Of course this would also overclock the CPU(s) from 867 MHz to 1.083 GHz and from 1.0 GHz to 1.25 GHz.

Divinity,
Quote:

Sorry, but I have to disagree: MDD 2003 with single G41250Mhz has 2Mb of cache. I have had one months ago! Read about it here:


http://www.everymac.com/systems/apple/powermac_g4/stats/powermac_g4_1.25_mdd.html

everymac has got it wrong. This is obvious because they don't mention a single 1.25Ghz model with 1MB cache at all, when it certainly exists.
This source has the correct info.

Ok, you are right, I was wrong. Sorry.

Argh so a dual system also at same clock will be always a bit faster (2MB VS 1MB), even o MorphOS..

> MDD 2003 (OS9.x capable)

Btw, it seems possible to make the FW800 OS9-compatible as well:

http://macos9lives.com/smforum/index.php?topic=762.msg3962#msg3962

@amigadave

In my honest opinion it is best to just use a single 1.25ghz card and overclock it to 1.5ghz. It is outperforming my 1.75ghz Mac Mini by a good margin for whatever reason. Games like to hiccup on the Mac Mini whereas my Mac MDD runs just great and uses much less CPU usage when I use emulators. Also, temperatures drop drastically with a single core cpu even using an aluminum heatsink. (though I have 3 MDD macs and several CPU cards and two spare logic boards.)

> It is outperforming my 1.75ghz Mac Mini by a good margin for whatever reason.

I think the reason is the L3 cache as you already suspected in other threads:

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=9084&forum=38&start=7
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=9265&forum=3&start=9

> temperatures drop drastically with a single core cpu

This is solely about single-core CPUs anyway, even when using a dual-CPU module ;-)

I been out of the loop for awhile so thanks for the links. :)

Isnt the CPU in the mac mini the same one that is used on a single cpu 1.25ghz in terms of caches?

Did some searching and the Mac Mini G4 uses a 7447a cpu, and the MDD macs use the 7455 cpu. The L3 cache is only 1MB on the single cpu 1.25GHz, but it is cheap enough of a card to overclock to 1.5GHz.

Just upgraded to 1.25GHz myself, had to desolder resistor R676 on the (133MHz FSB) logic board but everything went well. What's needed to go to 1.42GHz?