Mac Daniel's Advice

Overclocking a Slot-loading iMac

Dan Knight - 2009.02.12 - Tip Jar

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The 'iMac DV ClockUp' page was originally posted at <http://www.bekkoame.ne.jp/~t-imai/imacde1.html> and is no longer available there. We have adapted that information for the benefit of those who wish to overclock slot-loading iMacs. This may not apply to 500 MHz to 700 MHz iMacs that use the PowerPC 750CXe CPU, as they use a revised logic board. The original author is not known to us.

This infomation does not confirm stable operation. Please note that any modifications you make to your iMac are made at your own risk.

I analyzed how to increase the clock speed of an iMac DV. If you adjust the set of resistors labeled "R35" to "R42" on the logic board, you may configure the processor clock PLL.

First, remove the display connector cover.

Remove iMac bottom cover (6 screws).

Remove iMac bottom shield (6 screws).

Nonfigure the set of resistors labeled "R35" to "R42" on the logic board.

Resistor Settings

CPU Clock	PLLConfig	R35	R37	R39	R41	R36	R38	R40	R42
350 MHz	x3.5	x	S	S	S	S	x	x	x
400 MHz	x4	x	S	x	S	S	x	S	x
450 MHz	x4.5	S	S	S	x	x	x	x	S
500 MHz	x5	S	S	x	S	x	x	S	x
550 MHz	x5.5	S	x	x	S	x	S	S	x
600 MHz	x6	S	x	S	S	x	S	x	x
650 MHz	x6.5	S	x	S	x	x	S	x	S
700 MHz	x7	x	S	x	x	S	x	S	S
750 MHz	x7.5	S	x	x	x	x	S	S	S
800 MHz	x8	x	x	S	S	S	S	x	x
1 GHz	x10	x	S	S	x	S	x	x	S

S: mount resistor
x: remove resistor

P.S. Thank you for Mr.Nanko.

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