[mikellanes]

Hello, I have a G4 dual 867 with one bad processor, is there anyway to turn one off in open firmware? I can't run OS X with it only OS 9 righr now...

thanks anyone who can help

[Severed Hand of Skywalker]

How do you know you have one bad one?

[gatorparrots]

Disabling a Processor on a Multiprocessor System
http://developer.apple.com/qa/qa2001/qa1141.html

sudo nvram boot-args="cpus=1"

[Truepop]

That is really cool. I think I will do that just to see the preformace loss to convince my friends 2 is better than 1.

but if you can't boot in to os x I don't think that will do too much good.

[Kenneth]

I think CHUD can do that too...
it gave you a CPU.menu and CPU.prefPane to let you dis/enable the processor, L2/L3 cache on the fly.

Computer Hardware Understanding Development (CHUD) Toolkit

[mikellanes]

thanks I will try tomorrow!

I can boot in to X it just crashes everytime the second processor sees some action, I know it is the processor because of the kernel panic logs :-)

[Catfish_Man]

CHUD is DEFINITELY the best way of doing that.

[proton]

Of course CHUD isn't the best option if you can't boot OS X because the processor is faulty. The interface to disable the second processor in CHUD would require you to boot OS X in the first place...

- proton

[Catfish_Man]

Originally posted by proton:
Of course CHUD isn't the best option if you can't boot OS X because the processor is faulty. The interface to disable the second processor in CHUD would require you to boot OS X in the first place...

- proton

Oops. Good point. I was just thinking of turning off one proc in general.

[Link]

Funny, I ran that on my G4 out of curiosity and it still didn't quiet down the computer.

Now here's where it gets fun. I decided to pop open a terminal and run top to see if this really worked.

Dual 800 ..... had several programs running and top updating (with sorting) every 3 seconds:

Start off with 85% cpu free.

Turn off 2nd CPU: drops to 40% free

Turn off L3 cache: drops to 30%

Turn off L2 cache: drops down to a whooping 13%.

To the point, my computer started to feel sluggier then my bro's 800mhz imac O_O and it still had the 133 bus going!

I put back on the 2nd cpu but leave the cache options off.. jumps up to 75%, put on L2, jumps up to 85%, put on L3: jumps up to 90%.

Nice.

i guess having dual CPUs really DOES add a lot of UMPH to your computer o_O

[Graymalkin]

Originally posted by Link:
Funny, I ran that on my G4 out of curiosity and it still didn't quiet down the computer.

Now here's where it gets fun. I decided to pop open a terminal and run top to see if this really worked.

Dual 800 ..... had several programs running and top updating (with sorting) every 3 seconds:

Start off with 85% cpu free.

Turn off 2nd CPU: drops to 40% free

Turn off L3 cache: drops to 30%

Turn off L2 cache: drops down to a whooping 13%.

To the point, my computer started to feel sluggier then my bro's 800mhz imac O_O and it still had the 133 bus going!

I put back on the 2nd cpu but leave the cache options off.. jumps up to 75%, put on L2, jumps up to 85%, put on L3: jumps up to 90%.

Nice.

i guess having dual CPUs really DOES add a lot of UMPH to your computer o_O

Duh.

[Eug]

Are you sure it's not the RAM?

Have you tried a reformat?

[mikellanes]

It seems I still need to be in X in order to run any of these?

[Angus_D]

Boot into OF, (hold down cmd-opt-o-f) and do

Code:
setenv boot-args cpus=1
mac-boot

[mikellanes]

This dosen't seem to work, still shows 2 CPUs, I tried it a few times.

[Eriamjh]

How do you know it will disable the correct processor?

[mikellanes]

Good point ;-p

not that I can seem to get it to work

[Spliffdaddy]

can't you just physically unplug the processor?

[mikellanes]

not that I can see, they are both on one board, i could probably de-solder it but i would end up ruining the whole machine