I just software overclocked my G4 400 to 533MHz!

grabberslasher · 11:03 AM

I just software overclocked my Rev A. G4 400 to 533MHz!

Well, sort of. Following instructions on XLR8yourmac.com I went into the Open Firmware prompt and typed in a few commands to increase my system bus from 100MHz to 133Mhz.

Suddenly on restarting my G4 it happily proclaims to be a G4 533MHz in About this Mac and Apple System Profiler (10.2.5).

I was in a state of shock at first - over 25%. The XLR8yourmac article stated that it probably wont work over 50MHz but I have been running it at that speed for a few weeks now with less than 1º increase in heat.

Has anyone got any comments/suggestions (apart from EVACUATE!).

For those interested - these are the commands I typed (from xlr8):

"How to edit and store the NVRAMRC for 133MHz bus

(1) Boot by holding down "Cmd" + "Opt" + "O" + "F" keys to enter the OpenFirmware terminal.

(2) Enter the NVRAMRC editor. (<return> shows you should type "return" key)
nvedit <return>

(3) Type following script exactly (including spaces).

" /" select-dev <return>
7efdc44 " clock-frequency" get-my-property 2drop ! <return>
" /cpus/PowerPC,G4@0" select-dev <return>
1fca0554 " clock-frequency" get-my-property 2drop ! <return>
7efdc44 " bus-frequency" get-my-property 2drop ! <return>
1fbf711 " timebase-frequency" get-my-property 2drop !

(4) Type "Cntl" + "C" to exit NVRAMRC editor.

(5) Save the script
nvstore <return>

(6) To enable the NVRAMRC, type this command.
setenv use-nvramrc? true <return>

(7) Reboot with new timebase constant.
reset-all <return>

"

cc bcc · Apr 23, 2003, 11:33 AM

Can you provide a link to the article? I'd like to know of a way back when things go wrong. It's a cool hack!

grabberslasher · Apr 23, 2003, 11:38 AM

See the last step of the post:

"setenv use-nvramrc? true"

To undo any changes just type:
"setenv nvramrc? false"

All it does is tells the Open Firmware to run a setting script at startup.

To completely reset it just zap your PRAM -
Hold command-alt-p-r at startup.

Wait a minute while I get the URL.

grabberslasher · Apr 23, 2003, 11:39 AM

http://www.xlr8yourmac.com/G4ZONE/sa...CPUdesign.html

There you go.

jethroted · Apr 23, 2003, 12:03 PM

They say it does not work for OSX though.

That sucks.

grabberslasher · Apr 23, 2003, 12:32 PM

Of course it runs in OS X - as I said, I am using 10.2.5. It doesn't run on OS X prior to 10.1.1 (I think) - but who in their right mind would use such an early version of X at this stage?

Don't flame me for saying that!
It works perfectly - especially with it's new Geforce3Ti 64Mb graphics card and extra RAM - 384Mb.

The article also states that it will only read from two RAM slots and you must have 133MHz Ram to use it.

I have only the original RAM with my machine and all 4 slots are fully used after the hack.

grabberslasher · Apr 23, 2003, 12:35 PM

If you want screenshots/photos to prove it I can show you. The serial number on the back of the machine will prove that it was a 400MHz machine.

jethroted · Apr 23, 2003, 12:40 PM

Quote:

Originally posted by grabberslasher
Of course it runs in OS X - as I said, I am using 10.2.5. It doesn't run on OS X prior to 10.1.1 (I think) - but who in their right mind would use such an early version of X at this stage?

Don't flame me for saying that!
It works perfectly - especially with it's new Geforce3Ti 64Mb graphics card and extra RAM - 384Mb.

The article also states that it will only read from two RAM slots and you must have 133MHz Ram to use it.

I have only the original RAM with my machine and all 4 slots are fully used after the hack.

Sorry, I misread that part.

grabberslasher · Apr 23, 2003, 12:54 PM

Of the 120+ people who have viewed this thread do any others have any comments?

Say something...

gotohamish · Apr 23, 2003, 01:00 PM

Quote:

Originally posted by grabberslasher
Of the 120+ people who have viewed this thread do any others have any comments?

Say something...

Yeah, I do.

I have a Sawtooth G4 500, processor upgraded to 1.3Ghz, with the processor jumpers set for a 100Htz bus, anyone know how applying this hack would affect that?

grabberslasher · Apr 23, 2003, 01:30 PM

I could tell you if I knew your multiplier (for your upgrade card).

Your original multiplier is 5 (5x100Mhz) so your upgrade card must be 13(?!). I'm not sure, but multiply 133MHz by 13 for your end result.

1.729 GHz!

But I doubt that the hack will apply to your upgrade card. More likely it will only overclock your 500MHz (to 665). There's no harm in trying - I don't think a simple hack such as this can damage your computer. All it is is basically a startup setting.

True speed increase though.

Pentium Killer · Apr 23, 2003, 01:33 PM

I tried it and nothing happenened.Igot a G4 Sawtooth,too.Don´t I have to press return after

1fbf711 " timebase-frequency" get-my-property 2drop !

And what does type "Cntl"+"C" mean?
Directly after the line I quoted before?
So I have to type "Cntl" "C"?
What is this + for?Do I have to type it too?My god,this is not that easy

Pentium Killer · Apr 23, 2003, 01:43 PM

Anyway,#i give it a try again.

Pentium Killer · Apr 23, 2003, 02:06 PM

I tried again and nothing changed.Maybe I had some typos,I do not know.It is hard to see sometimes if I have to type space or not.

WannabeSQ · Apr 23, 2003, 02:33 PM

Quote:

Originally posted by gotohamish
Yeah, I do.

I have a Sawtooth G4 500, processor upgraded to 1.3Ghz, with the processor jumpers set for a 100Htz bus, anyone know how applying this hack would affect that?

Well, this hack basically overclocks the bus to 133, so it might help the upgraded processor indirectly. You will have to change the multipliers on the Gigadesigns card to the 133mhz bus versions to get 1.33ghz. I bet it would help your performance. The only reason it "overclocks" the processor is the bus running faster. Most of the time when u overclock the bus you downclock the multiplier on the processor so you dont fry it.

I might try it on my sawtooth 500, I can't permanently break anything if it doesn't work right? and if I do, it would just be the processor right? I was planning on gettin a faster one anyway....

digitalgiant · Apr 23, 2003, 03:18 PM

Will this work on a 667 PB? My baby is starting to show its age.

grabberslasher · Apr 23, 2003, 03:19 PM

Cntrl C means press
the control button and c at the same time. Like command-c for copying.

Trust me, it does work.

Yes you must press return after each line. Spaces are also important.

ecino1 · Apr 23, 2003, 03:54 PM

WOW. I just tried this on my AGP G4 400, and it worked!!! I attached a screen shot to prove it. It shows 133mhz bus and a machine speed of 533mhz. I cant tell if it is any faster so far. Is there a way to test this? Hey, other guy that did this, does yer machine seems faster? Let me know.

Nipsy · Apr 23, 2003, 03:54 PM

I tried the similar hack on my MDD 867, and the computer presented info of a faster bus, but the machine was not running any faster.

Do a pair of XBench tests to see if there is an actual difference going on.

ecino1 · Apr 23, 2003, 04:12 PM

Sorry, here is the screen shot. I will do xbench now and compare the results.

me hate windows · Apr 23, 2003, 04:17 PM

i am still confused about the ram, would my pc100 still work?

ecino1 · Apr 23, 2003, 04:26 PM

About the RAM, when i did the hack all 4 of my ram modules were recognized! Sadly, when i used xbench on the computer while the hack was applied my xbench score was only 46.24, which is lower than my original xbench test score of 50.03 taken just before applying the firmware hack!! I don;t understand why this would actually SLOW DOWN my machine, even if it just was displaying fake information. Well, it didnt seems to do any harm, and zapping the p-ram returned my system to normal. I guess others could give it a try and see if they get better results, but i doubt this actually does anything beneficial.

Hemingray · Apr 23, 2003, 04:50 PM

Quote:

Originally posted by grabberslasher
I just software overclocked my Rev A. G4 400 to 533MHz!

Be careful... technically a "Rev A. G4 400" is the Yikes G4, not the Sawtooth.

Fortunately I know that this would not work on my Yikes G4 (as the Yikes is overclocked by changing the jumpers on the mobo), but if someone else with a Yikes G4 came along and tried this, it could possibly screw up their computer. (Not sure about that, but messing with OF is never a light matter...)

Anyways, I would suggest clarifying that by "Rev A." you mean Sawtooth.

grabberslasher · Apr 24, 2003, 03:26 AM

I don't see why the 350MHz G4 (Yikes) would be classed as a Rev A. - it came out at the same time as the Sawtooth model.

Let's just say "early Sawtooth G4s" (originally 400-450MHz after Apple reduced the speeds of the lineup).

In other words - if you have a Sawtooth G4 with a green glowing power button you can do this.

It is untested on later G4s (white glowing power button).

I tried the X bench tests and got a score of about 52.4 on mine (compared to about 49). I don't see why yours might have slowed down. Interesting.

grabberslasher · Apr 24, 2003, 03:29 AM

I just checked my G4 - one of my newer RAM sticks is actually 133MHz RAM. Maybe it only speeds up your computer if you have faster RAM. I'll try taking out the stick and checking X Bench.

Apr 23, 2003, 11:00 AM	#1
grabberslasher macrumors 6502 Join Date: Aug 2002 Location: Éire	I just software overclocked my G4 400 to 533MHz! I just software overclocked my Rev A. G4 400 to 533MHz! Well, sort of. Following instructions on XLR8yourmac.com I went into the Open Firmware prompt and typed in a few commands to increase my system bus from 100MHz to 133Mhz. Suddenly on restarting my G4 it happily proclaims to be a G4 533MHz in About this Mac and Apple System Profiler (10.2.5). I was in a state of shock at first - over 25%. The XLR8yourmac article stated that it probably wont work over 50MHz but I have been running it at that speed for a few weeks now with less than 1º increase in heat. Has anyone got any comments/suggestions (apart from EVACUATE!). For those interested - these are the commands I typed (from xlr8): "How to edit and store the NVRAMRC for 133MHz bus (1) Boot by holding down "Cmd" + "Opt" + "O" + "F" keys to enter the OpenFirmware terminal. (2) Enter the NVRAMRC editor. (<return> shows you should type "return" key) nvedit <return> (3) Type following script exactly (including spaces). " /" select-dev <return> 7efdc44 " clock-frequency" get-my-property 2drop ! <return> " /cpus/PowerPC,G4@0" select-dev <return> 1fca0554 " clock-frequency" get-my-property 2drop ! <return> 7efdc44 " bus-frequency" get-my-property 2drop ! <return> 1fbf711 " timebase-frequency" get-my-property 2drop ! (4) Type "Cntl" + "C" to exit NVRAMRC editor. (5) Save the script nvstore <return> (6) To enable the NVRAMRC, type this command. setenv use-nvramrc? true <return> (7) Reboot with new timebase constant. reset-all <return> " Last edited by grabberslasher; Apr 23, 2003 at 11:03 AM.
	0

Apr 23, 2003, 11:38 AM	#3
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	To undo See the last step of the post: "setenv use-nvramrc? true" To undo any changes just type: "setenv nvramrc? false" All it does is tells the Open Firmware to run a setting script at startup. To completely reset it just zap your PRAM - Hold command-alt-p-r at startup. Wait a minute while I get the URL.
	0

Apr 23, 2003, 11:39 AM	#4
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	The URL http://www.xlr8yourmac.com/G4ZONE/sa...CPUdesign.html There you go.
	0

Apr 23, 2003, 12:03 PM	#5
jethroted macrumors 6502a Join Date: Jan 2003 Location: Cyberspace	They say it does not work for OSX though. That sucks. __________________ Hey pink boy, get some slack in your life before the stark fist of removal comes for you!
	0

Apr 23, 2003, 12:32 PM	#6
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	What? Of course it runs in OS X - as I said, I am using 10.2.5. It doesn't run on OS X prior to 10.1.1 (I think) - but who in their right mind would use such an early version of X at this stage? Don't flame me for saying that! It works perfectly - especially with it's new Geforce3Ti 64Mb graphics card and extra RAM - 384Mb. The article also states that it will only read from two RAM slots and you must have 133MHz Ram to use it. I have only the original RAM with my machine and all 4 slots are fully used after the hack.
	0

Apr 23, 2003, 11:33 AM	#2
cc bcc macrumors 6502 Join Date: Jul 2001 Location: nl	Can you provide a link to the article? I'd like to know of a way back when things go wrong. It's a cool hack!
	0

Apr 23, 2003, 12:35 PM	#7
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	Screenshots If you want screenshots/photos to prove it I can show you. The serial number on the back of the machine will prove that it was a 400MHz machine.
	0

Apr 23, 2003, 12:54 PM	#9
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	? Of the 120+ people who have viewed this thread do any others have any comments? Say something...
	0

Apr 23, 2003, 01:30 PM	#11
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	I could tell you if I knew your multiplier (for your upgrade card). Your original multiplier is 5 (5x100Mhz) so your upgrade card must be 13(?!). I'm not sure, but multiply 133MHz by 13 for your end result. 1.729 GHz! But I doubt that the hack will apply to your upgrade card. More likely it will only overclock your 500MHz (to 665). There's no harm in trying - I don't think a simple hack such as this can damage your computer. All it is is basically a startup setting. True speed increase though.
	0

Apr 23, 2003, 01:33 PM	#12
Pentium Killer macrumors member Join Date: Apr 2002 Location: Berlin	I tried it and nothing happenened.Igot a G4 Sawtooth,too.Don´t I have to press return after 1fbf711 " timebase-frequency" get-my-property 2drop ! And what does type "Cntl"+"C" mean? Directly after the line I quoted before? So I have to type "Cntl" "C"? What is this + for?Do I have to type it too?My god,this is not that easy
	0

Apr 23, 2003, 01:43 PM	#13
Pentium Killer macrumors member Join Date: Apr 2002 Location: Berlin	Anyway,#i give it a try again.
	0

Apr 23, 2003, 02:06 PM	#14
Pentium Killer macrumors member Join Date: Apr 2002 Location: Berlin	I tried again and nothing changed.Maybe I had some typos,I do not know.It is hard to see sometimes if I have to type space or not.
	0

Apr 23, 2003, 03:18 PM	#16
digitalgiant macrumors regular Join Date: May 2002 Location: Knoxville Tenneesse	Hmmmmm Will this work on a 667 PB? My baby is starting to show its age. __________________ Join MacRumors.com - Team Folding, and be a part of the #1 Mac Folding team!
	0

Apr 23, 2003, 03:19 PM	#17
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	Cntrl C means press the control button and c at the same time. Like command-c for copying. Trust me, it does work. Yes you must press return after each line. Spaces are also important.
	0

Apr 23, 2003, 03:54 PM	#18
ecino1 Banned Join Date: Feb 2002 Location: Canada	cool!! WOW. I just tried this on my AGP G4 400, and it worked!!! I attached a screen shot to prove it. It shows 133mhz bus and a machine speed of 533mhz. I cant tell if it is any faster so far. Is there a way to test this? Hey, other guy that did this, does yer machine seems faster? Let me know.
	0

Apr 23, 2003, 03:54 PM	#19
Nipsy macrumors 65816 Join Date: Jan 2002	I tried the similar hack on my MDD 867, and the computer presented info of a faster bus, but the machine was not running any faster. Do a pair of XBench tests to see if there is an actual difference going on. __________________ But then again, whereas Apple is being run by a brilliant marketer with the uncanny ability to bend people to his will, Gateway is being run by a man perfectly willing to go on television and show the world that he solicits business advice from a talking cow...
	0

Apr 23, 2003, 04:12 PM	#20
ecino1 Banned Join Date: Feb 2002 Location: Canada	Sorry, here is the screen shot. I will do xbench now and compare the results. Attached Thumbnails
	0

Apr 23, 2003, 04:17 PM	#21
me hate windows macrumors 6502 Join Date: Jan 2002	ram i am still confused about the ram, would my pc100 still work? __________________ "You are coming to a sad realization, cancel or allow?"
	0

Apr 23, 2003, 04:26 PM	#22
ecino1 Banned Join Date: Feb 2002 Location: Canada	followup About the RAM, when i did the hack all 4 of my ram modules were recognized! Sadly, when i used xbench on the computer while the hack was applied my xbench score was only 46.24, which is lower than my original xbench test score of 50.03 taken just before applying the firmware hack!! I don;t understand why this would actually SLOW DOWN my machine, even if it just was displaying fake information. Well, it didnt seems to do any harm, and zapping the p-ram returned my system to normal. I guess others could give it a try and see if they get better results, but i doubt this actually does anything beneficial.
	0

Apr 24, 2003, 03:26 AM	#24
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	I don't see why the 350MHz G4 (Yikes) would be classed as a Rev A. - it came out at the same time as the Sawtooth model. Let's just say "early Sawtooth G4s" (originally 400-450MHz after Apple reduced the speeds of the lineup). In other words - if you have a Sawtooth G4 with a green glowing power button you can do this. It is untested on later G4s (white glowing power button). I tried the X bench tests and got a score of about 52.4 on mine (compared to about 49). I don't see why yours might have slowed down. Interesting.
	0

Apr 24, 2003, 03:29 AM	#25
grabberslasher Thread Starter macrumors 6502 Join Date: Aug 2002 Location: Éire	I just checked my G4 - one of my newer RAM sticks is actually 133MHz RAM. Maybe it only speeds up your computer if you have faster RAM. I'll try taking out the stick and checking X Bench.
	0

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