[The Dude]

I came across this thread over at XLR8yourmac.com's forums where this guy put a dip switch in place of the tiny resisters that govern the CPU's clockspeed.
http://bbs.xlr8yourmac.com/ubb/Forum11/HTML/000045.html

I am wondering, would this be possible on a Mac like a Pismo or an iBook? I know Sine would love to be able to easily overclock his blueberry iBook. While we are at it, how about iMacs? Cubes?

Any feedback?

[Steph]

The short answer is yes, it should.

The longer answer, after all the usual caveats about safety and risk to your computer and so on, is that the space in a laptop is very, very tight. Looking at my iBook here, I suppose a small hole could be cut beside the speaker or the power button and a dip-switch pack could be mounted flush so the case could still close all right.

--Stephanie

[TheAnunnaki]

I have always done it with jumper boards that i fit somewhere in the Mac near the pads of the resistors.

Especially with the more recent macs where you might end up soldering for hours to get the best setting, this is a little more work in the beginning, but afterward your live is easier...

Every PowerMac is clocked the same way, but Apple uses a different set of chips in almost every Mac. but the basics is that the processor has dedicated pins for the multiplication factor of the bus clock which ends up in the CPU clock rate.

On older Macs you connect these pins to your new DIP switch board and disconnect the signals (CFG0..CFG3) from the mainboard (usually by removing the resistors on the board).

On some Macs, you already have jumper blocks, such as the Gossamer and the Yosemite Macs.

As for WallStreet PowerBooks, for example, there is hardly room for switches as i think, but one might have success wtih SMD DIP switches. I have tried to reclock my PowerBook from 292/83 Mhz to 333/66Mhz but I ended up withalmost killing a wiring on the tiny board so I decided not to tamepr around any longer...

The easiest way to overclock a Mac is to replace the base clock generator with one using a higher frequency. but this results in different timebase for the system clock as well. And you also reclock the PCI and memory bus besides the fact that other internal stuff such as video system also gets another timebase. its funny only, not for real use ;-)

[Crimson]

and in iMacs...there are 2 rows for resistors, so that makes 3 rows for connectors, one should be able to use 3-point switches instead...I mean, swithes with 2 resistors so that the center is connected, and the switch "decides" which one of the resistors get it...u got the picture...

[Eric the Fen]

Well, after o/c'ing my ibook from 300-400mhz, i am convinced the easier path is a switch method, best place to put it (the switch) is under the keyboard, theres enough space near where the airport cable snakes into the innards of the machine, one thing i AM looking at as well is removing the speaker and mounting a fan there in place, ...ahhh space, the final frontier ...LOL
If i were able to fit a fan there then i would seriously look at adding a small circuit near the audio out socket and mounting stereo speakers (approx. same size as original spkr) at the base of the lcd casing, making sure tho' that the circuit allows the speakers to mute when external speakers/headphones are connected..
BTW, the length of wire from the switch to the smd's is not a drama, despite what anyone may say, just make sure the wire guage is small to be on the safe side, last thing you'd wanna do is to start resoldering in there, LOL
Share and Enjoy...
Eric the Fen....