Granite's 2006 to 2008 Mac Pro Upgrade Guide

[mac567]

The only thing I can think of is there there are 2 rom types for 5770 32bit and 64bit EFI. So 2006 is 32bit and 2008 64bit!
Or perhaps one of your processors is marginal faulty but my 2006 power supply drives 2 dual core X5272 3.4ghz processors an efi flashed 7870, a 1tb velociraptor, SSD and 2 pcie cards fine and 16gb of 800mhz ram!

 

[JacquesL]

The only thing I can think of is there there are 2 rom types for 5770 32bit and 64bit EFI. So 2006 is 32bit and 2008 64bit!
Or perhaps one of your processors is marginal faulty but my 2006 power supply drives 2 dual core X5272 3.4ghz processors an efi flashed 7870, a 1tb velociraptor, SSD and 2 pcie cards fine and 16gb of 800mhz ram!

Thanks for the confirmation about the 2006 PSU. Seems like a red herring.
Do you know for sure that the 5770 exists in a 32 bits only EFI?

 

[mac567]

try netkas.org forum

search on netkas.org forum but I seem to remember the roms are different and some are not interchangeable between 32bit and 64bit systems

 

[JacquesL]

Successful Upgrade

Amazingly the 2006-2008 upgrade has been successful.
After the 2008 motherboard swap the MacPro wouldn't boot with the 5770 Graphic card.
I removed the GPU, and installed the hard drives to see if the Mac would boot. It booted just fine.
I re-installed the graphic card and ... it booted this time.
Time to finalize the installation ...
Thank you the Wolf...

 

[JacquesL]

Update on HD 5770 boot error

I actually found that connecting the Mini Display Port is what is causing the failure to boot!
Using the DVI port enable the system to boot. I was able to install Yosemite without problem. So far no issue...
I suspect that the issue is with the HD 5770 firmware. Time to look if there is an update available...

 

[ededoad]

I ran across this thread when I got too the will not boot part . I had already ordered a 3,1 power supply. I guess I will save it if ever needed. As this post is a few years after the last post I will include todays price for the conversion.

47.95 Fans
139.00 Logic board
33.00 2- 2.8 GHZ Xeon CPU
28.49 Wiring harness
79.95 Memory Risers

318.39 Total including shipping
I reused the 1,1 memory cage modified with a file and some scrap carbonite plastic.
I made a deflector from some scrap aluminum as the 2008 3,1 had and pinched it between the heat sinks.
I still had problems with the fans and had to use an after market free download to get them under control. Understand that may have something to do with the SMC. Might worry about that later but not today.

Seems that my fan issues are caused by a faulty heatsink monitor. Temp monitor program shows it at 127C cpu 32C but the heatsink is cool to the touch.

Fan problem was a unplugged north bridge heat sensor. That I forgot to put on the parts list($20)

Interesting thread. Thank you.
Regards, Ed

 

[luigi60]

I am indeed using my 2006 PSU and it is working perfectly for me.

For a backup I do plan to buy a proper 2008 PSU eventually, but so far after all these months I havent had a single problem with my current setup!

My 2006 PSU doesn't start with mac 3.1 logic board, i used 2.8 quad core, new reise for ram, 8 gb (8x1) of fb 800 mhz ram, radeon 4870 gpu card ecc. It flash some led and stop fast. Can You tell me some right way to resolve the issue?

 

[ededoad]

My 2006 PSU doesn't start with mac 3.1 logic board, i used 2.8 quad core, new reise for ram, 8 gb (8x1) of fb 800 mhz ram, radeon 4870 gpu card ecc. It flash some led and stop fast. Can You tell me some right way to resolve the issue?

Do you have a 3,2 wire harness? If not it will not start. Ebay about 25 dollars.
Regards, Ed

 

[luigi60]

Do you have a 3,2 wire harness? If not it will not start. Ebay about 25 dollars.
Regards, Ed

Why buy another cable if i have just one? The cable fits in the sokets, should be only correctly wired i suppose. Can i find the correct pin out of the socket on the main board relative at the ps3 cable?
Thank you.

 

[ededoad]

Why buy another cable if i have just one? The cable fits in the sokets, should be only correctly wired i suppose. Can i find the correct pin out of the socket on the main board relative at the ps3 cable?
Thank you.

Why buy another cable if i have just one? The cable fits in the sokets, should be only correctly wired i suppose. Can i find the correct pin out of the socket on the main board relative at the ps3 cable?
Thank you.

The power supply cables are different. No one has said what the pinouts are and I have no idea where they are published.
Don't worry about the power supply it will work but you need a 2008 cable.
Regards, Ed

 

[luigi60]

The power supply cables are different. No one has said what the pinouts are and I have no idea where they are published.
Don't worry about the power supply it will work but you need a 2008 cable.
Regards, Ed

In every way i thank you for the answers, i'll buy this cable and i'll try to understand the differences betwin the 2 versions of them.
Regard.

 

[nigelbb]

Thanks for reviving this old thread that I must have missed first time round.

As I understand it provided that you have a Mac Pro 3,1 wiring harness then you can just install a Mac Pro 1,1 or 2,1 power supply & it will all work? I wish that I had known that last year when the power supply in my 3,1 failed as of course I already had the 3,1 wiring harness.. The going rate on eBay UK for a 1,1 or 2,1 power supply is less than half that of a power supply for a 3,1.

 

[luigi60]

Thanks for reviving this old thread that I must have missed first time round.

As I understand it provided that you have a Mac Pro 3,1 wiring harness then you can just install a Mac Pro 1,1 or 2,1 power supply & it will all work? I wish that I had known that last year when the power supply in my 3,1 failed as of course I already had the 3,1 wiring harness.. The going rate on eBay UK for a 1,1 or 2,1 power supply is less than half that of a power supply for a 3,1.

Not just so...i upgraded my mac 2.1 to 3.1 and i want use my 2.1 PSU on the 3.1 logic board, but the way it doesn't starts with the 2.1 set of wiring harnes. The sokets are the same and with my multimeter also the ground connections are the same, should be a difference on the C harnes i believe, but for this i need to know the pin out scheme about this harness. I think should be the PS-ON pin different placed.
Regard.

 

[luigi60]

Update about mac pro 1.1 PSU on Mac pro 3.1.
After lot of test about the starting issues i found that on the ps2 soket on 3.1 board the pins 2 and 9 are not ground poles as in the 1.1/2.1 boards. So i decided to cut and after this the psu starts, fan runs, but no chime and no video, the led of cpus A and B lights fix red. I don't know if for the missing correct connections on pin 2 and 9 or if the cpus are bricked, by the way if i get off the cpus the PSU doesn't starts and also i feel that when PSU starts the heat sinks of cpu warms, so i believe is only by the missing wiring on the 2 and 9 pins. Somebody can check what is connected on that poles in a running system?

 

[luigi60]

Last update about 1.1's PSU on 3.1 logic board. To make the PSU starts nedds only to cut 2 wires on the ps2 harness. Looking at the plugger from behind (wires side) with the clip on top, the second pin on top left and the fourth on botton (2 and 9 pins). This cause that on the 1.1 board they are ground and on the 3.1 board they are 12V, 12v1 and 12v2 in order, cause of the greater ampers of the 2.8 ghz cpus. For a good work you should to cut the wires on pins 7 and 2 from ps3 (12pins harness near the pcie power sockets) and connect them on the pins 2 and 9 in order on the ps2 harness. Make this modifies only if you have experienses in electronic, right items, solder etc, and at your own risk. Good luck!

 

[IIcx]

Don't mean to be bumping this thread back from the dead, but wanted to update it with a few things I ran into on my 1,1 when I converted it over this weekend that may help others.

Using my 2006 1,1 as a base, I purchased the following 2008 3,1 parts:

Wiring harness
Logic board
Northbridge cooler
Memory risers
Memory cage
CPU cover

Biggest issues I ran into were from re-using my 1,1's case:

So issues some covered before, some not:

1. 3,1 wiring harness is short. Lugi60 in his posts above outlined how to reuse/modify the original 1,1 harness but I was not feeling quite that brave, so I took the 3,1 harness route. If you use the 3,1 wiring that upper fan bulk head between the optical drive and PSU will mess your day up.
Its thick steel, and I suppose you could grind out the connector holes to allow the PSU wires to thread through it, but I decided to remove it entirely. I would not recommend doing that though, it was a nightmare and ended up with some bent aluminum that thankfully is hidden with the door on. There is just no easy way around this thing ether way. With the bulk head removed I ended up holding the fan in place with some rubber bumpers that came off the floor of the case under the memory cage. It holds very nicely.

2. Its been mentioned before as well, but reusing the original front fan assembly results in a one inch air gap outlined above, regardless if you use the 3,1 or 1,1 CPU cover. Ether replace the front fans or tape the gap/leave it be. The original 1,1 cover does hold on solidly if you decide to skip replacing this.

3. One last big thing that was not nearly bad as that upper fan bulkhead was the memory riser/cage and the logic board standoffs. The 1,1 uses two logic board standoffs marked in red to hold the cage in. The 3,1 uses four marked in green, and the holes don't line up.
To fix this, with the logic board out I just grabbed the standoffs with some pliers and wiggled them back and forth until they popped off. Then screwed the 3,1 logic board into the case. Using an ink cartridge out of an old bic pen I ripped apart, I stuck it through the four holes on the 3,1 board and marked where they were. Out came the logic board again, and this time I very slowly and carefully drilled on those marks four very shallow wells in the outer case wall so as to not go through. Then taking the bit out of the drill, took its sharp edge and gouged the living daylights out of the edges of the new holes to give the epoxy something to hold onto. Since there are only two stand offs from the 1,1 board, I ended up just moving them to the top two holes. Covered the holes in a light covering of epoxy, stuck the standoffs in the mess, and then screwed the 3,1 logic board back down. The new standoffs did not quite line up but with the bic pen cartridge stuck through the screw holes I was able to pull them back inline with where they needed to be and then just let it the epoxy set.

The 3,1 uses a few more logic board standoffs than the 1,1 did, so you will have a few empty screw holes when your done but the only ones that need to be moved are the memory cage mount ones. Also the cage has a screw hole that does not line up that attaches it to the lower base of the case (in the pic above). I just left it, the fronts enough to secure it but it would be easy to drill out the rear hole to fix this.


So with 3,1's being so cheap now was the above worth it? Probably not.

3,1 parts are cheap, and 1,1's are cheaper. My 1,1 came from a University salvage sale for $50 bucks, and If you don't factor in the 6 hours I wasted messing around with this (which is the fun part) I maybe only have about $150 bucks into something that with a few small upgrades and a little bit more fiddling can run Sierra which seems kind of neat. Anyways if you decide to go this route best of luck and have fun.

 

[MysticIce]

Sorry to awake this tread. Can someone explain how would the 08 harness fit into the 06 power supply. Have a working 1,1 MP and a dead 3,1 MP (psu faulty). What would the first procedure be

 

[vinaypundith]

I just successfully converted a 2007 model Mac Pro 2,1 to a 2008 model Mac Pro 3,1.

First, I'd like to clarify what Luigi60 wrote above about the PSU cable wiring. The ONLY difference in the PSU cable socket pinouts on the motherboards between the 2006 / 2007 model Mac Pro 1,1 / 2,1 and the 2008 model Mac Pro 3,1 is in the PS#2 / J2 connector (which is the 10-pin connector in the lower-left corner of the board, near the CPU-B socket). The difference is with pins 4 and 7 (the pin numbers are written on the wires side of the connector on the cable). Pins 4 and 7 are ground wires in the 2007 model Mac Pro 2,1, but in the 2008 model Mac Pro 3,1 pin 4 goes to the 12V1 line and pin 7 goes to the 12V2 line. Pin 4 needs to be connected to the 12V1 pin right beside it (Pin 5), and Pin 7 needs to be connected to the 12V2 line right beside it (Pin 6).
To fix it, I cut the wires coming from pin 4 and 7 (at the logic board end of the PSU cable) about 3 inches away from the connector, sleeved the tips 3" long pieces, then shaved the insulation off of the Pin 5 and Pin 6 wires right at the point where the sleeved Pin 4 and 7 wires would touch them, and then soldered the sleeved end of the Pin 4 wire to the shaved spot on the Pin 5 wire, and the sleeved end of the Pin 7 wire to the shaved spot on the Pin 6 wire. Then cover the other cut ends of the 2 ground wires (we don't need them for anything) and the soldered spots with electrical tape or heat shrink tubing (remember to put the heat shrink tubing piece on the wire before soldering it!)
You do NOT need to do anything to the PS#3 / J3 cable, or buy any new cables.
It's really a lot simpler to do than my description may make it sound. If you have the technical skill to rebuild a Mac Pro with a new motherboard, you can definitely do this cable modification easily.

Also, my Mac Pro 2,1's hard drive which had an installation of Mac OS X 10.11 El Capitan modified with the 32-bit EFI ("Pike" modification, I think it's called) didn't boot up after upgrading the computer's logic board to that of a Mac Pro 3,1. It would show the bootup Apple logo, have the progress bar go to about 2/3 of the way, and then the screen would go blank. For it to work, I had to download a fresh Mac OS X 10.11 El Capitan installer (from https://www.macworld.co.uk/how-to/mac-software/download-old-os-x-3629363/ ), create a new install media (instructions below), then boot the rebuilt computer from installation disk, and reinstall Mac OS. When it asked what drive to install Mac OS on, I selected the same one that had the old installation on it (with the intention of overwriting the old non-working installation), but it instead did a repair of the existing installation so that when it was done the computer booted right into my old Mac OS installation, without having lost any data, settings or applications. Worked out great for me, but if you plan to do that I'd still recommend backing up all your data.
IMPORTANT: Make the new Mac OS installation media BEFORE disassembling and rebuilding your Mac Pro 1,1 or 2,1, if you don't have another Apple computer available!! You need a working Mac OS computer (probably x86-64 CPU-based) to make the new installation disk. I didn't realize this, and had to use another MacBook to do it.
To make the Mac OS installation disk, download the new Mac OS file from the above link, mount the DMG image, and run the InstallOSX.pkg file in it. Don't worry, it won't actually start reinstalling Mac OS. It only creates a new "application" on the computer, which if you run, it will start installing Mac OS. To create an installation media, don't run it, but instead use a terminal command that references it, which you can find here : https://www.macworld.co.uk/how-to/mac-software/bootable-mac-installer-3575875/
Once you have Mac OS v10.11.6 El Capitan installed and running properly, you can try upgrading it further using the Mac OS Sierra / High Sierra / Mojave / Catalina Patcher tools.
If you are upgrading your computer's video graphics card at the same time as the logic board, and plan to upgrade Mac OS past the v10.11.6 that Apple officially supports on the Mac Pro 3,1, be sure not to get an AMD Radeon HD 5000 or 6000 series video card. The website says that those aren't compatible with the Mac OS Sierra / High Sierra / Mojave / Catalina Patcher tools.

The rest of the process is just as everyone else in this forum thread has written. Luckily for me the upgrade worked on the first try.

I am, though, having trouble with the fan speeds. The CPU_MEM and EXHAUST fans run at full speed unless I use a 3rd party fan speed control tool, creating a jet engine type noise whenever the computer is on. Also, the PSU fan isn't running at all. Does anyone here know a fix for that? I am using all the old fans from the Mac Pro 2,1.

I also am yet to do anything about the RAM memory card riser cage, which has a different mounting hole pattern on the new one and is a different size. So far I have just held the RAM risers in with their connector slots and packaging tape.

Here is how much this upgrade has cost me, in early April 2020 (all parts were sourced from eBay):
$46 for the new Mac Pro 3,1 logic board, model 820-2128-B / 630-7997
$22 for a pair of Intel Xeon E5472 CPUs
(Yes, the Xeon CPUs with a 1600MHz front-side-bus speed will work with 667MHz RAM sticks. No need to get new RAM)
$22 for a pair of new RAM riser cards, model 820-2178 / 630-8751. The Mac Pro 3,1's riser cards are quite different from those used by the Mac Pro 1,1 and 2,1.
$11 for a new northbridge chip heatsink
As for the GPU: I am yet to get one. I'll update this when I get one.
The NVidia GeForce 7300GT video card original to the Mac Pro 2,1 didn't work at all after the upgrade / rebuild (no video output at all). If you have that, you'll definitely need to upgrade it, but if you have something newer I'm not sure.

I've attached a pinout for the Mac Pro 2,1's PSU. The perspective of the image is looking into the plug of the connector on the cable. I've circled the 2 ground wires in cable #2 that need to be made into 12V lines to work with the Mac Pro 3,1's logic board.

Thanks to everyone on this forum who has provided instructions and experiences doing this. It really made my job a lot easier than it would have been without them.

 

[vinaypundith]

Sorry to awake this tread. Can someone explain how would the 08 harness fit into the 06 power supply. Have a working 1,1 MP and a dead 3,1 MP (psu faulty). What would the first procedure be

@MysticIce :
If you are trying to transplant the 2006 1,1 PSU into the 2008 3,1 computer, it should be a drop-in replacement, except maybe for differences in the cable length. The PSUs themselves are the same, I believe.

 

[galletti1]

I just successfully converted a 2007 model Mac Pro 2,1 to a 2008 model Mac Pro 3,1.

First, I'd like to clarify what Luigi60 wrote above about the PSU cable wiring. The ONLY difference in the PSU cable socket pinouts on the motherboards between the 2006 / 2007 model Mac Pro 1,1 / 2,1 and the 2008 model Mac Pro 3,1 is in the PS#2 / J2 connector (which is the 10-pin connector in the lower-left corner of the board, near the CPU-B socket). The difference is with pins 4 and 7 (the pin numbers are written on the wires side of the connector on the cable). Pins 4 and 7 are ground wires in the 2007 model Mac Pro 2,1, but in the 2008 model Mac Pro 3,1 pin 4 goes to the 12V1 line and pin 7 goes to the 12V2 line. Pin 4 needs to be connected to the 12V1 pin right beside it (Pin 5), and Pin 7 needs to be connected to the 12V2 line right beside it (Pin 6).
To fix it, I cut the wires coming from pin 4 and 7 (at the logic board end of the PSU cable) about 3 inches away from the connector, sleeved the tips 3" long pieces, then shaved the insulation off of the Pin 5 and Pin 6 wires right at the point where the sleeved Pin 4 and 7 wires would touch them, and then soldered the sleeved end of the Pin 4 wire to the shaved spot on the Pin 5 wire, and the sleeved end of the Pin 7 wire to the shaved spot on the Pin 6 wire. Then cover the other cut ends of the 2 ground wires (we don't need them for anything) and the soldered spots with electrical tape or heat shrink tubing (remember to put the heat shrink tubing piece on the wire before soldering it!)
You do NOT need to do anything to the PS#3 / J3 cable, or buy any new cables.
It's really a lot simpler to do than my description may make it sound. If you have the technical skill to rebuild a Mac Pro with a new motherboard, you can definitely do this cable modification easily.

Also, my Mac Pro 2,1's hard drive which had an installation of Mac OS X 10.11 El Capitan modified with the 32-bit EFI ("Pike" modification, I think it's called) didn't boot up after upgrading the computer's logic board to that of a Mac Pro 3,1. It would show the bootup Apple logo, have the progress bar go to about 2/3 of the way, and then the screen would go blank. For it to work, I had to download a fresh Mac OS X 10.11 El Capitan installer (from https://www.macworld.co.uk/how-to/mac-software/download-old-os-x-3629363/ ), create a new install media (instructions below), then boot the rebuilt computer from installation disk, and reinstall Mac OS. When it asked what drive to install Mac OS on, I selected the same one that had the old installation on it (with the intention of overwriting the old non-working installation), but it instead did a repair of the existing installation so that when it was done the computer booted right into my old Mac OS installation, without having lost any data, settings or applications. Worked out great for me, but if you plan to do that I'd still recommend backing up all your data.
IMPORTANT: Make the new Mac OS installation media BEFORE disassembling and rebuilding your Mac Pro 1,1 or 2,1, if you don't have another Apple computer available!! You need a working Mac OS computer (probably x86-64 CPU-based) to make the new installation disk. I didn't realize this, and had to use another MacBook to do it.
To make the Mac OS installation disk, download the new Mac OS file from the above link, mount the DMG image, and run the InstallOSX.pkg file in it. Don't worry, it won't actually start reinstalling Mac OS. It only creates a new "application" on the computer, which if you run, it will start installing Mac OS. To create an installation media, don't run it, but instead use a terminal command that references it, which you can find here : https://www.macworld.co.uk/how-to/mac-software/bootable-mac-installer-3575875/
Once you have Mac OS v10.11.6 El Capitan installed and running properly, you can try upgrading it further using the Mac OS Sierra / High Sierra / Mojave / Catalina Patcher tools.
If you are upgrading your computer's video graphics card at the same time as the logic board, and plan to upgrade Mac OS past the v10.11.6 that Apple officially supports on the Mac Pro 3,1, be sure not to get an AMD Radeon HD 5000 or 6000 series video card. The website says that those aren't compatible with the Mac OS Sierra / High Sierra / Mojave / Catalina Patcher tools.

The rest of the process is just as everyone else in this forum thread has written. Luckily for me the upgrade worked on the first try.

I am, though, having trouble with the fan speeds. The CPU_MEM and EXHAUST fans run at full speed unless I use a 3rd party fan speed control tool, creating a jet engine type noise whenever the computer is on. Also, the PSU fan isn't running at all. Does anyone here know a fix for that? I am using all the old fans from the Mac Pro 2,1.

I also am yet to do anything about the RAM memory card riser cage, which has a different mounting hole pattern on the new one and is a different size. So far I have just held the RAM risers in with their connector slots and packaging tape.

Here is how much this upgrade has cost me, in early April 2020 (all parts were sourced from eBay):
$46 for the new Mac Pro 3,1 logic board, model 820-2128-B / 630-7997
$22 for a pair of Intel Xeon E5472 CPUs
(Yes, the Xeon CPUs with a 1600MHz front-side-bus speed will work with 667MHz RAM sticks. No need to get new RAM)
$22 for a pair of new RAM riser cards, model 820-2178 / 630-8751. The Mac Pro 3,1's riser cards are quite different from those used by the Mac Pro 1,1 and 2,1.
$11 for a new northbridge chip heatsink
As for the GPU: I am yet to get one. I'll update this when I get one.
The NVidia GeForce 7300GT video card original to the Mac Pro 2,1 didn't work at all after the upgrade / rebuild (no video output at all). If you have that, you'll definitely need to upgrade it, but if you have something newer I'm not sure.

I've attached a pinout for the Mac Pro 2,1's PSU. The perspective of the image is looking into the plug of the connector on the cable. I've circled the 2 ground wires in cable #2 that need to be made into 12V lines to work with the Mac Pro 3,1's logic board.

Thanks to everyone on this forum who has provided instructions and experiences doing this. It really made my job a lot easier than it would have been without them.

Thanks for this post!!! I've been trying to figure this out for a while and won't bore you with the details but Wolf's and your post have made it possible to finish. Just to double check. You wound up basically "jumping" wire 4 wire 5 and wire 7 into wire 6 leaving nothing connected to pins 4 and 5 and using the 2,1 PSU and it worked? Or did you "join" wires 4 and 5 and 6 and 7 so that all four pins receive 12V?

 

[vinaypundith]

Thanks for this post!!! I've been trying to figure this out for a while and won't bore you with the details but Wolf's and your post have made it possible to finish. Just to double check. You wound up basically "jumping" wire 4 wire 5 and wire 7 into wire 6 leaving nothing connected to pins 4 and 5 and using the 2,1 PSU and it worked? Or did you "join" wires 4 and 5 and 6 and 7 so that all four pins receive 12V?

I "joined" wires 4 and 5 and 6 and 7 so that all 4 pins receive 12V. What I left unconnected were the wires coming from the power supply side that used to connect to pins 4 and 7 on the motherboard.
I'm currently writing this from the upgraded Mac Pro - running OS Catalina with dosdude's patcher.
[automerge]1592919497[/automerge]

I am, though, having trouble with the fan speeds. The CPU_MEM and EXHAUST fans run at full speed unless I use a 3rd party fan speed control tool, creating a jet engine type noise whenever the computer is on. Also, the PSU fan isn't running at all. Does anyone here know a fix for that? I am using all the old fans from the Mac Pro 2,1.

I also am yet to do anything about the RAM memory card riser cage, which has a different mounting hole pattern on the new one and is a different size. So far I have just held the RAM risers in with their connector slots and packaging tape.

As for the GPU: I am yet to get one. I'll update this when I get one.
The NVidia GeForce 7300GT video card original to the Mac Pro 2,1 didn't work at all after the upgrade / rebuild (no video output at all). If you have that, you'll definitely need to upgrade it, but if you have something newer I'm not sure.

To clarify a few things I left hanging in my original post:
Fan speeds: No issue. I forgot to plug in the temperature sensor on the northbridge heatsink and the cable for the PSU fan.

GPU upgrade: I went with a GTX680 for $80. I got a Galaxy brand GTX680 4GB model and reflashed it with EFI-modded firmware. If you're doing this, do NOT get the Galaxy 680 4GB model. It's not listed as compatible in the forum thread for GTX680 reflashing, and although I have it working great in MacOS, if I try to install Windows I get very frequent display glitches and driver crashes.

RAM memory card riser: I hacked the old one to work. See the attached pictures.

 

[galletti1]

Your, sir, deserve a beer! It finally worked! Basically you clip #4 and #7 wires and get #5 wire to output to both #4 and #5 pins and #6 wire to both #6 and #7 pins. I get a chime which is much further than I've gotten but none of my graphics cards work with this setup (MSI GT 710, GEForce GTX570 or NVIDIA 7300GT).

 

[Zlobnick]

I want to report a successful 1,1 PSU swap into a 3,1 machine, using the original 3,1 PSU housing. My 3,1 machine started to power off randomly so I thought I'd replace it's problematic PSU with a more reliable 1,1 one. The only caviat is that I had to solder the original 3,1 power socket because the replacement PSU came without it (only PCBs), but it was a pretty quick and simple. I tought I'd share some pictures because there are almost noothing online to compare against. The cables were long enough and it's pretty straightforward. Some 10 screws and some patience The machine works great and doesn't power off anymore. It runs Unigine Heaven GPU benchmark with a Radeon RX570 on a Monterey 12.0.1 just fine

 

[pc297]

I "joined" wires 4 and 5 and 6 and 7 so that all 4 pins receive 12V. What I left unconnected were the wires coming from the power supply side that used to connect to pins 4 and 7 on the motherboard.
I'm currently writing this from the upgraded Mac Pro - running OS Catalina with dosdude's patcher.
[automerge]1592919497[/automerge]

To clarify a few things I left hanging in my original post:
Fan speeds: No issue. I forgot to plug in the temperature sensor on the northbridge heatsink and the cable for the PSU fan.

GPU upgrade: I went with a GTX680 for $80. I got a Galaxy brand GTX680 4GB model and reflashed it with EFI-modded firmware. If you're doing this, do NOT get the Galaxy 680 4GB model. It's not listed as compatible in the forum thread for GTX680 reflashing, and although I have it working great in MacOS, if I try to install Windows I get very frequent display glitches and driver crashes.

RAM memory card riser: I hacked the old one to work. See the attached pictures. View attachment 926840 View attachment 926843 View attachment 926844 View attachment 926845 View attachment 926846

Did anyone ever try the MP 1,1/2,1 risers on a 3,1 motherboard?