Re: Hmmmmm
sure it would work! except for the fact that your pb is already running on a 133mhz system bus...
sure it would work! except for the fact that your pb is already running on a 133mhz system bus...
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I just software overclocked my G4 400 to 533MHz!
- Thread starter grabberslasher
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Apple's cpus are both software and hardware controlled. For lack of better explanation the OS more than likely asks OF what the speed is. OF will return the value of the cpu(s). The cpu's will run at that speed. Now, if you mess with OF and the OS asks it what speed are you running at and OF says the new speed, the OS will report the new speed but the hardware controls won't allow the cpu's to change to the new speed.
Basically OF is only fooling the OS and not the cpu's.
Basically OF is only fooling the OS and not the cpu's.
It made my machine quite a bit faster. I was actually amazed but the specs do state that my machine should be 33% faster.. let's see what the benchmarks say:
CocoaBench (tot - numbers - image - i/o)
400 MHz: 6.01 - 5.57 - 8.52 - 4.39
533 MHz: 7.46 - 7.60 - 10.28 - 4.35
faster: 24% - 36% - 20% - -1%
Xbench (Tot - CPU - Thread - Memory - Quartz - OpenGL - UI - Disk)
400 MHz: 41.24 - 32.54 - 29.09 - 55.57 - 55.15 - 46.47 - 51.18 - 36.50
533 MHz: 43.93 - 38.30 - 30.37 - 65.30 - 55.05 - 46.78 - 51.89 - 38.20
6.5% - 17.7% - 4.4% - 17.5% - -0.2% - 0.6% - 1.3% - 4.6%
processor temperature measurement
"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."
Is this the processor temperature? If so, how did you measure it? I've been looking for a temperature measurement utility for G4 processors like Thermograph was for G3s.
"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."
Is this the processor temperature? If so, how did you measure it? I've been looking for a temperature measurement utility for G4 processors like Thermograph was for G3s.
How does this bus overclock work with CPU upgrades?
I just bought a PowerLogix 1.4 Ghz G4 for my Sawtooth. Of course, right after installing it I found this info on bus overclocking. I'd like to try overclocking my bus (I've got PC133 RAM) but I don't want to fry my new CPU. I can test it out with my original 500Mhz G4 chip.
Basically, the problem with the new CPU is that it doesn't have jumpers so I don't know if I can change the multiplier. It's currently at 14 but I'd want only 10.5 to keep the same speed on a 133Mhz bus. Can I change this setting? Will it set itself automatically (I wish)? Will my chip fry if I run it at 1.8 Ghz?
Link
I just bought a PowerLogix 1.4 Ghz G4 for my Sawtooth. Of course, right after installing it I found this info on bus overclocking. I'd like to try overclocking my bus (I've got PC133 RAM) but I don't want to fry my new CPU. I can test it out with my original 500Mhz G4 chip.
Basically, the problem with the new CPU is that it doesn't have jumpers so I don't know if I can change the multiplier. It's currently at 14 but I'd want only 10.5 to keep the same speed on a 133Mhz bus. Can I change this setting? Will it set itself automatically (I wish)? Will my chip fry if I run it at 1.8 Ghz?
Link
Would it be suicide to try this on my PowerBook 1.25 G4? If I got DDR 400 memory (PC3200), would it be able to take a 200 mhz. bus???
This is what is happening.
I did this to my G/F's iBook.
Its actually O/C'ed to 600Mhz and 100 Mhz bus up from 500 and 66Mhz.
I did Openfirmware to correct the OS X bad reporting of the speed...but I typed it wrong! Now it thinks its 100 Mhz. But the performance is actually faster then before.
XBench is probably slower because it probably divides the resuts by the clock to get a score...
Didn't you guys read the whole thread? It does not overclock your computer, except on the Sawtooth, if you try with another one all it does is change what your computer reports it as, but does not really change it's operating speed.
Maybe. 167MHz to 200MHz isn't that big of a jump. Your cpu could then run at 1.5GHz at the same 7.5X bus multiplier. This seems like a reasonable amount to overclock with good hardware components.Originally posted by illumin8
Would it be suicide to try this on my PowerBook 1.25 G4? If I got DDR 400 memory (PC3200), would it be able to take a 200 mhz. bus???
yikes doesn't work?
I'm confused. The top of this thread says a G4 400 Rev A was used. Isn't that a yikes? Another post says only sawtooth will work. Which is it?
Ps - overclocked my yikes to 450 mhz using jumpers. anyone else do this?
I'm confused. The top of this thread says a G4 400 Rev A was used. Isn't that a yikes? Another post says only sawtooth will work. Which is it?
Ps - overclocked my yikes to 450 mhz using jumpers. anyone else do this?
Re: yikes doesn't work?
Yes, I also have a jumper-overclocked Yikes running at 450 (problem-free for a little over two years now).
The firmware hack was done on an Sawtooth G4. The poster just made a mistake by saying it was a "Rev. A". He must have meant "Rev. B." You're right, a Rev. A. G4 400 is a Yikes without question.
Yes, I also have a jumper-overclocked Yikes running at 450 (problem-free for a little over two years now).
The firmware hack was done on an Sawtooth G4. The poster just made a mistake by saying it was a "Rev. A". He must have meant "Rev. B." You're right, a Rev. A. G4 400 is a Yikes without question.
Please read the article at xlr8yourmac again. The only way to increase the bus frequency from 100MHz to 133MHz is by removing the resistors at R434 and R435, which can be found on the back of the motherboard. These resistors are jumpers which tell the SG500 clock generator chip which frequency to operate at. A time-base problem resulted in OSes before OS 9.1 and OS 10.1.2 with the overclocked bus, which the firmware hack was designed to fix. The OF hack DOES NOT affect the speed of your computer, only the way it's speed is reported to the OS. Besides, PC100 RAM would almost certainly not run at 133MHz.
Well, you could get it to run at 133, but you'd probably fry it or get some serious crash action going on
maybe not but...
I really don't know if it actually sped up my machine or not. BUT, I can now run age of mythology on my G4, which I was unable to do before I moved the jumpers. So, if it fools the software, and still works, I'm happy.
I really don't know if it actually sped up my machine or not. BUT, I can now run age of mythology on my G4, which I was unable to do before I moved the jumpers. So, if it fools the software, and still works, I'm happy.
Re: maybe not but...
I think you're mixing up clock speed and bus speed. Changing the jumpers in your Yikes G4 overclocked your processor to 450MHz from 400MHz, that's all. It didn't touch your bus speed. What jamall is referring to is the bus speed only, which has nothing to do with what you did with your jumpers.
Originally posted by profgaw101
I really don't know if it actually sped up my machine or not. BUT, I can now run age of mythology on my G4, which I was unable to do before I moved the jumpers. So, if it fools the software, and still works, I'm happy.
I think you're mixing up clock speed and bus speed. Changing the jumpers in your Yikes G4 overclocked your processor to 450MHz from 400MHz, that's all. It didn't touch your bus speed. What jamall is referring to is the bus speed only, which has nothing to do with what you did with your jumpers.
Speaking from experience, I would highly recommend you leave R434 and R435 alone. I removed them and I regret it. I am running 10.3.2 on a G4 400 and nothing is stable anymore. I have five different pairs of PC133 memory modules old and new and none of them help with the stability. Also, you will render two of your memory slots useless. I am now limited to 512mb as I can only use the two lower DIMM slots.
I will be ordering replacement resistors to solder back on as the speed increase is not worth the problems it has caused. iTunes and iMovie crash all of the time and I have yet to rip an entire disc to the hard drive.
I just need to find out what value those resistors were. If anyone knows, please send me an IM through the forum.
Thanks,
Bill Shelly
bshelly, the resistors don't have any resistance, they just acted as jumpers. If you didn't leave too much of a mess behind when you removed them you can simply use a conductive pen to bridge the gaps. Otherwise just solder on a length of wire. When I upped the bus multplier ratio on my processor daughter card, I found it was a lot safer to cut the traces leading to the resistors with a scalpel blade than actually remove the resistors themselves. Repairing a trace with a pen is a lot easier than resoldering a resistor. Another method I've heard of is putting a small strip of masking tape down the middle of the jumpers and drawing the connections onto the tape with the pen. It would be easier just to fork out for a Digital Audio board on ebay than risk the bus overclock. Good luck with those repairs.
PS. did you reduce the bus multiplier on your processor daughter card at the same time as the bus overclock? If not then your 400MHz processor will still be running at 4x the bus, or 533MHz, which it likely can't handle. 3.5x, or 466MHz, is probably more realistic, which involves removing R7 and R11 on your processor card (R9 should already be absent and R13 should already be in place). Hope this helps.
PS. did you reduce the bus multiplier on your processor daughter card at the same time as the bus overclock? If not then your 400MHz processor will still be running at 4x the bus, or 533MHz, which it likely can't handle. 3.5x, or 466MHz, is probably more realistic, which involves removing R7 and R11 on your processor card (R9 should already be absent and R13 should already be in place). Hope this helps.
jamall,
Thanks for the info. I wasn't sure if the resistors had any resistance. I suppose I should have measured them first to be sure. Soldering a jumper wire should not be too difficult for me, otherwise I think your idea of a conductive pen or even window defroster repair paint should work.
I did not modify the G4 400mhz card multipliers, but I also have a Giga Designs 1.4ghz chip that will work at 100 or 133mhz bus speed. At 100mhz it seemed much more stable. Sorry for not mentioning that before. I must have been tired.
I would eventually like to get a Digital Audio board, but they are a bit expensive still.
I will adjust back to 100mhz this weekend and report back on stability.
Thanks for you help!
Bill Shelly
Thanks for the info. I wasn't sure if the resistors had any resistance. I suppose I should have measured them first to be sure. Soldering a jumper wire should not be too difficult for me, otherwise I think your idea of a conductive pen or even window defroster repair paint should work.
I did not modify the G4 400mhz card multipliers, but I also have a Giga Designs 1.4ghz chip that will work at 100 or 133mhz bus speed. At 100mhz it seemed much more stable. Sorry for not mentioning that before. I must have been tired.
I would eventually like to get a Digital Audio board, but they are a bit expensive still.
I will adjust back to 100mhz this weekend and report back on stability.
Thanks for you help!
Bill Shelly
One other thing...
When I removed the resistors, I lost the ability to use all four DIMM slots. I could only use the two closest to the AGP card.
I'm not sure why that happened, but I will be back up to 1GB ram sometime this weekend.
Thanks,
Bill Shelly
When I removed the resistors, I lost the ability to use all four DIMM slots. I could only use the two closest to the AGP card.
I'm not sure why that happened, but I will be back up to 1GB ram sometime this weekend.
Thanks,
Bill Shelly
I finally got around to soldering a jumper wire to where my resistors used to be. My system board is now back to 100Mhz Front Side Bus and everything is stable now. Too bad I cannot fully utilize this PC133 memory. Oh well. At least I can now run with a full 1GB of RAM.
-Bill
-Bill
The moral of the story is:
If it ain't broke, don't fix it!
Oh well, good thread anyway, if a bit confused.
If it ain't broke, don't fix it!
Oh well, good thread anyway, if a bit confused.