Yoo!

Finally had some time this weekend to tinker with the G5 towers. I bought a CPU set off fleabay for $30 which were the 2.5ghz cpus. Upon inspection it did not look promising. The "white rice" could be seen along side the CPU itself. Figured since the guy sold it to me as "working", I plugged in the whole thing. This caused the logic board not to even power on! Just acted dead. That did not look promising and figued the CPU set was shot.

I figured I might as well remove each CPU off the LCS and have a look, and to my surprise, the "white rice" had blue/green rice as well! Some was on the CPU card itself. Since there was nothing more to lose, I used a toothbrush and some 90% alcohol and scrubbed at the cpu board to remove as much of it as I could. I then grabbed a spare heatsink set I had from some 2.0s and applied new thermal paste. I first used my 2.7ghz G5 tower which I knew worked. After hitting the power button, WHALA! it booted.... :)

Now was the actual testing I meant to try... I then removed the 2.5ghz cpu set from the 2.7ghz g5 I had, and then brought out my 2.0ghz g5. I swapped out the CPUs and pressed the power button... It powered up, but I heard no "chime", and figured it didn't work. I then remembered this G5 tower had its volume turned all the way down so of course you wouldn't hear a chime. I attached a screen and I was greeted with the "folder" icon since I had no HDD attached.

So there you have it. A 2.0ghz board CAN and WILL clock to 2.5ghz max speed. This 2.0ghz G5 is the "newer" revision model that has the 8 memory bank slots. Before you do such swapping, be sure to update to the newest Boot Rom.

**I noticed when MorphOS boots up, it "quiets" down the fans and they do low RPMS. This of course will start to heat up the CPUs at uncomfortable levels (80c), so might as well swap out the fans for something that flows air MUCH better. You have been warned. :)**

2.5ghz memory test

CPU info 2.5ghz

Thank and enjoy your day!

Congrats!
Thanks for the research!

I have a 2.3ghz that I'd like to upgrade to 2.7ghz.
Anyway to test this?
thanks


P.S. I will be dropping in a 256gb ssd this evening in my power mac g5 2.3.
I believe this will improve the b.o.c.h.s. emulator dramatically. I am putting in a lot of hours getting XP to run good in b.o.c.h.s.



[ Edited by bash64 04.08.2013 - 14:46 ]

Is overclocking or just changing the cpus in the g5's?.

What is the latest BIOS available for mac G5?

@bash64

You will have to see via Mac OS X. Check your boot rom version. Off hand I forget what revision my 2.7ghz logic board has, but its one that isnt offered online. 5.2.4f1 is the one shown on this 2.7ghz board. If yous shows that revision, you may be in luck on such an upgrade, but if yours shows to be older then that, I would say it can't be done because I tried upgrading the 2.0ghz board to some 2.7ghz CPUs but it didnt POST.

@_ThEcRoW

Just swapping CPUs. :)

Can you remove one of the cpus and still get MOS booted?
I'd like to remove the extra weight.
This G5 is killing my back.

I believe you have to have both of them in for the system to even boot up. Not sure if or how it is done to remove an extra CPU and get the system to go.

Had to take the testing a step further and see if I could "calibrate" the 2.5ghz CPUs to the board... Here is the results:

Calibration Results for 2.5ghz CPU Swap

**My 2.7ghz board would never calibrate correctly and kept throwing a "CPU intake fan speed error". I also heard horror stories of ASD Tool actually bricking the logic board, so again, do it at yer own risk! :)**

ok, what about a 2.3->2.5 upgrade?

I don't see why not :) This 2.0 tower was probably released the same time around as the 2.3ghz. The thing is, there was newer released boot rom boards released/being manufactured at the time. There is a 50/50 shot your's might be one with a newer boot rom. Can you obtain an OS X install cd? All you need is just to boot the CD and go into System Profiler to see what boot rom you have. :)

Doesn't showconfig show the rom version?

@bash64

I believe not. I just dug up these instructions. Might be worth a shot:

1. Shut down.
2. Start up and hold down cmd-opt-o-f
3. The Boot ROM Revision is displayed at the top of the screen.
4. Type "bye" followed by <return> to continue starting up in Mac OS.

Let us know. :)

Going home in 30 minutes.
Will post my rom then.

Will also be installing a 256gb ssd tonight.
Gonna be killer speed.

I have rom 5.2.4.f1 on my mac g5 2.3ghz


I just replaced the main hard drive with a 256gb ssd.
It is now unbelievably fast.

However, for some strange reason I have seen no improvement with the running of Windows XP using the b.o.c.h.s. emulator.
Back to tweaking...

@Doffo: You done much more that an entire mac world did not in g5 cpu upgrade. Many many mac site just replies cpu swapping don't possible. My feelings was just nobody bother to try it, because the cost, because lack of knowledge.
Congrat again.

@Derringer
thanks. i appreciate the kind input.

@bash64
That is GOOD news. thats the boot rom my current 2.7 g5 has... :) its risking it but imma bet a 2.7 cpu set will boot up. thing is most setups are leaking so convert it to heatsinks and calibrate using the Apple service diagnostics CD. get the one that supports G5

I have already bought all the fans, molex connectors, and heat sinks.
I think you provided the ebay links to do so.
I only see one 2.7 set on ebay:

http://www.ebay.com/itm/Apple-G5-CPU-PROSESSOR-DUO-2-7-GHZ-with-Liquid-Cooling-Heatsink-603-6220-A-/121106601274?pt=CPUs&hash=item1c3284153a

@doffo,

What is the part number on your 2.7ghz cpus?
I don't want to buy the wrong thing.
Thanks

Also, is there anyway you can message me the name of a torrent that will download the apple cd to resync the cpus?

Will a cpu set from an xserve or a HP server work?


[ Edited by bash64 05.08.2013 - 17:52 ]

> Will a cpu set from an xserve or a HP server work?

There were HP servers with PPC970?

I dont know if an HP ever had those.. :P

Also, I don't think there were 2.7ghz xserve g5 cpus, but I did successfully swap some xserve 2.3ghz and they did just fine. :)

> I don't think there were 2.7ghz xserve g5 cpus

True, 2.3 Ghz was maximum.

http://en.wikipedia.org/wiki/Xserve#Xserve_G5

Does anyone have a set of 2.5 cpus they can sell me?
Buying from ebay is somewhat risky.
Better yet, do you have a set of 2.7 cpus?
thanks

I found a torrent with all 25gb worth of Apple Service Diagnostic CDs.
I had to use a shell command called dmg2img.exe to convert the file into an iso:
>dmg2igm.exe {source}.dmg {dest}.iso

Burned the 2.5.8 cd and I passed all the tests.
It ran my fans so hard the g5 sounded like a jet engine.

I seen a few sets of 2.5ghz on ebay for a decent price...

$38ish after shipping. Least the auction says they work.

2.5ghz g5 CPU set on ebay

I was able to swap 2.7ghz Processors into a board that had 2.3. I bought both machines, but the LCS from the 2.7 machine had leaked and destroyed the PSU in that unit. After I clean the processor boards and mounted the heatsinks from the 2.3 I was able to get it to boot. Only issue is with ASD 2.5.8 the system would power off after about 5 min of thermal calibration. So I swapped motherboards but now I get the dreaded intake fan speed error during calibration.

Trying to build the optimal MorphOS/Classic Mac PPC game machine. Managed to nab a 2.5ghz set of processors with one of the better LCS modules on it so I'll see what I can do with that. There is a recycler in town that has these PCI-X 7,3 G5's on sale for $30 CDN or so if you watch it enough so I've got a few machines. I have my old Quad G5 machine that needs the LCS rebuilt but since it's not MorphOS supported I've pushed that project back. I'm gonna try a few things with the thermal calibration and report back. Might just end up sticking the 2.3's back in it since the gains would be marginal really to 2.7GHz. I bought both the 2.7 and 2.3 machine for around $30 so it's just fun to tinker, I also have a Dual 1.8 machine I have to pick up this week that I bought for $24. I figure it'll be good for spare parts.