Who here has overclocked macs?

joecool85

macrumors 65816
Original poster
Mar 9, 2005
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I overclocked a Quadra 650 with a 33mhz 68040 processor to 42mhz 2 years ago when it was my webserver. It worked at 44mhz but crashed every 2-3 days so I had to bring it back down to 42.

I also recently overclocked my 266mhz beige g3 to 315mhz with no problems. No crashes at all, seems to run fine. The temp didn't even rise.

Anyone done any OC on their macs?
 

California

macrumors 68040
Aug 21, 2004
3,766
40
joecool85 said:
I overclocked a Quadra 650 with a 33mhz 68040 processor to 42mhz 2 years ago when it was my webserver. It worked at 44mhz but crashed every 2-3 days so I had to bring it back down to 42.

I also recently overclocked my 266mhz beige g3 to 315mhz with no problems. No crashes at all, seems to run fine. The temp didn't even rise.

Anyone done any OC on their macs?
No, but had it done to three Tibooks by Daystar. 400 - 550mhz.

Excellent.
 

joecool85

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Mar 9, 2005
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As far as I know nobody has really done any G5 overclocks. And quite frankly I'm not sure I would even try. For one, I don't like overclocking new equiptment, for two, they are already so hot I wouldn't want to make things worse.
 

Nermal

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Dec 7, 2002
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Is that true? I remember when the 1.42 GHz G4s came out, people claimed that they were overclocked 1.25s, yet Motorola's printing on the processors clearly stated that they were 1.42 GHz.
 

highres

macrumors 6502a
Jul 1, 2005
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Near the Singularity
Thanks for the info...So to confirm the answers:

2.7 PM's already run pretty hot as it is, so why up the temp any further by overclocking?

2.7 PM's are essentially overclocked 2.5's and are already maxed out processor speed-wise? Is this true?
 

joecool85

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Mar 9, 2005
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highres said:
Thanks for the info...So to confirm the answers:

2.7 PM's already run pretty hot as it is, so why up the temp any further by overclocking?

2.7 PM's are essentially overclocked 2.5's and are already maxed out processor speed-wise? Is this true?
AFAIK the 2.5 PM was an overclocked 2.3, because 2.3 was as fast as IBM could get the G5 otherwise, and the 2.7 is an overclocked 2.5. Keep in mind, it is not an overclocked 2.5 out of the 2.5 PMs, it is an overclocked actual 2.5
 

highres

macrumors 6502a
Jul 1, 2005
518
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Near the Singularity
joecool85 said:
AFAIK the 2.5 PM was an overclocked 2.3, because 2.3 was as fast as IBM could get the G5 otherwise, and the 2.7 is an overclocked 2.5. Keep in mind, it is not an overclocked 2.5 out of the 2.5 PMs, it is an overclocked actual 2.5
Thanks, I guess my line of questioning is fairly pointless because with dual 2.7's I have all the processor speed I really need for most processor intensive tasks, but as they say "the grass is always greener..." :rolleyes:
 

link92

macrumors 6502
Aug 15, 2004
335
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The last I heard was that the G5s are rated by IBM upto 2.3GHz for air cooling, and 2.7GHz for water cooling...
 

camomac

macrumors 6502a
Jan 26, 2005
765
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Left Coast
seems like a very risky and possibly very expensive venture just to squeeze a few more mhz.
in the peecee world, it doesn't seem like such a big deal, because alot of the processors (classic examples: celeron 300a, P4 1.6a, and P4 2.4c) were underclocked anyways so squeezing of some more juice was not that big of a deal.
i just would not want to risk it.
 

dmw007

macrumors G4
May 26, 2005
10,635
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Working for MI-6
camomac said:
seems like a very risky and possibly very expensive venture just to squeeze a few more mhz.
in the peecee world, it doesn't seem like such a big deal, because alot of the processors (classic examples: celeron 300a, P4 1.6a, and P4 2.4a) were underclocked anyways so squeezing of some more juice was not that big of a deal.
i just would not want to risk it.
-Very true, I myself overclocked my former PeeCee from a 3.06GHz P4 up to a 3.3/3.4GHz P4 and it ran relatively stable (for a PeeCee).

-MacAddict Magazine ran an article on how to overclock the 1.25GHz G4 in the Mac Mini up to 1.5GHz.
 

highres

macrumors 6502a
Jul 1, 2005
518
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Near the Singularity
in addition to my PM 2.7, I do have an old Sawtooth G4 400 Mhz I use as a webserver, wouldn't mind squeezing a little more out of the processor, can someone post a link on how to overclock it? Thanks in advance...
 

.:*Robot Boy*:.

macrumors 6502
Jan 21, 2005
373
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New Zealand
I overclocked my Blue and White G3 from 350MHz up to 400MHz. 50MHz may not seem like much, but it's a 14% increase in clock speed, which is pretty good considering I only had to spend a dollar or so on some jumpers. I wish I'd known that this could be done when I bought the thing :rolleyes:.

I've tried getting it up to 450MHz, but it refuses to start up. Is it worth trying a different heatsink or something? I know that they shipped a 450MHz model later on which presumably just had a different jumper configuration and a better heatsink?
 

joecool85

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Mar 9, 2005
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.:*Robot Boy*:. said:
I overclocked my Blue and White G3 from 350MHz up to 400MHz. 50MHz may not seem like much, but it's a 14% increase in clock speed, which is pretty good considering I only had to spend a dollar or so on some jumpers. I wish I'd known that this could be done when I bought the thing :rolleyes:.

I've tried getting it up to 450MHz, but it refuses to start up. Is it worth trying a different heatsink or something? I know that they shipped a 450MHz model later on which presumably just had a different jumper configuration and a better heatsink?
With a different heat sink you *most likely* could squeeze more out of it. However, if it won't even start up with it set like that, odds are it is just too much for the chip. What they do when they make these chips is make a bunch of G3s, the ones stable at 450 go into one pile, the ones only stable at 400 go into another pile etc etc etc, it works this way with all chips. And every chip is a little different, just like human faces (good analogy I found on an overclocking website,) so they will all OC differently.

**edit**
With some searching it became apparent that iMacs are not easily OC'ed and even if they are, tend to overheat due to inadequate cooling.

Overclocking of a Sawtooth 400 up to 450 seems pretty stable, here is a link: http://www.xlr8yourmac.com/G4ZONE/G4YIKESOC/
 

840quadra

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Feb 1, 2005
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I have a G4 ZIF @450MHz in my B&W G3. I have overclocked it slightly to 500 MHZ. It is running Folding@Home 24/7 (Pegs the CPU 24/7) and haven't had any heat / crashing issues.

I would like to try other computers in my collection, but I am not sure there is a way to correctly accomplish faster speeds.

 

eXan

macrumors 601
Jan 10, 2005
4,713
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Russia
- What is better: frying your new shiny Mac for a dew more MHz (no real world difference in speed) or using what you have for looong time period?

- Of course frying you new system!!!


:D

Thats the answer of all overclockers ;)
 

RedTomato

macrumors 601
Mar 4, 2005
4,014
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.. London ..
I underclocked my AMD Duron 700 to 600. Seems to make the system far more stable, which was what mattered to me.

Actually happened by accident - I first overclocked it to 800 MHz, ran that for a while, then forgot about the speed setting in daily use. A couple of months later, while checking something else, discovered it had reset itself at some point to run at 600 MHz.

Thinking about it, I realised that I had noticed no difference whatsoever between 800 and 600, but that it had seemed more stable recently. So I left it like that :D

some people underclock their processors so that they can run them fanless. Seems worthwhile to me.

cheers

RedTomato