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Home Forums 68kMLA PowerLogix 1.1GHz upgrade only running at 650MHz — #5
Post #5 by trag
Source Forum68kMLA
CategoryOS 9
Post DateFri, 12 Mar 2010 - 23:32
Original URLhttps://68kmla.org/bb/threads/powerlogix-1-1ghz-upgrade-only-running-at-650mhz.20150/
Post
Hmm, for some reason I'm getting no quote button at the bottom of messages.

Anyway, if you're getting 650 MHz when set to a 11:1 ration, then the bus speed of your B&W must be set to 650/11 = 59.1 MHz.

Clearly, the software (CPU Director) expects the bus speed to be 100 MHz, which would give you 100 MHz X 11 = 1100 MHz.

You could try setting CPU Director to a higher multiplier. I'm not sure what the choices are, although, IIRC 20:1 is the highest. 20:1 should give you 1182 MHz, which might be a bit too fast. If there's an 18:1 or 19:1 setting try those.

Alternatively, go over to xlr8yourmac.com and read the articles on setting the jumpers in the B&W then reset yours so that you can actually get a 100 MHz bus speed. Bus speed is the only jumper setting on the B&W motherboard you care about with that upgrade. The cache ratio and CPU speed multiplier settings are ignored by the PPC750GX upgrade.

Wasn't it the case that some B&Ws would do 100 MHz and some would only do slower bus speeds, or am I misremembering. That is, they all had the settings for all teh speeds, but on some the hardware (chips) weren't chosen for the 100 MHz bus speed?

mp.ls