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13 Can I increase the speed of my Mac by accelerating the clock? (Macintosh hardware)




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This article is from the Macintosh hardware FAQ, by Elliotte Rusty Harold elharo@shock.njit.edu with numerous contributions by others.

13 Can I increase the speed of my Mac by accelerating the clock? (Macintosh hardware)

Apple engineers designed the Mac IIsi to run at 25 megahertz. Apple
marketeers made them reduce the speed by 20% so as not to hurt sales
of the IIci. Thus with various caveats it is generally safe to
accelerate a IIsi to 25 MHz by changing the clock chip. All other
Mac models were designed to run at the speeds they normally run at so
"clock-chipping" them is a much iffier proposition. Compact Macs,
PowerBooks and the Mac II, IIx and IIcx as well as the LC and LC II
use the same oscillator to time various external circuitry as they
use to time the CPU so they almost never work if the clock chip is
replaced. Most other Macs seem to work for at least a while when
sped up by as much as twenty percent. Somewhere beyond a twenty
percent increase in clock speed most Macs experience serial port
problems though the exact level of safe increase varies from Mac to
Mac even within the same model and configuration. Other problems may
surface over time as the extra heat generated by the faster speed
increases the wear and tear on the insides of the Mac.

Performing this upgrade is not for the faint of heart. It is quite
complex and requires soldering, replacement of several parts, and
other non-trivial procedures. If done improperly it can result in
major, expensive damage to your Mac. I am not going to give detailed
instructions for doing this here. If you do want to do this
yourself, check out

<URL:http://bambam.cchem.berkeley.edu/~schrier/mhz.html>
<URL:ftp://rever.nmsu.edu/pub/macfaq/info/Clock_Chip_History.txt>
<URL:ftp://rever.nmsu.edu/pub/macfaq/info/Clock_Chip_Centris_610.txt>
<URL:ftp://rever.nmsu.edu/pub/macfaq/info/Clock_Chip_IIsi.txt>
<URL:ftp://rever.nmsu.edu/pub/macfaq/info/Clock_Chip_Quadra_700.txt>

For people who are willing to open their Mac and swap out RAM or a
hard drive but don't feel comfortable soldering on their motherboard,
KS Labs, (614) 373-0353, offers $165 kits that more safely (no
soldering) accelerate the clock. These kits include a clip-on
oscillator plus a heat sink and fan to keep the faster circuitry
cool.

 

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