View Full Version : PowerMac G4 MDD and 1.25 Ghz Dual Processor

Feb 23, 2010, 03:57 AM
Hello macrumors
bought 1.25 dual processor for my g4 on ebay
but for some reason the processor does not work = \
I installed it in my powermac g4 mdd 1 GHz, added thermal compound, secured the radiator, the computer turns on the process of identification of USB-devices, but after about 15 seconds it starts to make noise like an airplane and all = \
may need to update the firmware, switch some jumpers or something else?
I use Google translator, so Sorry for the broken english

Feb 23, 2010, 05:08 AM
Just a suggestion. After making sure that your MDD isn't using the 133 bus (it shouldn't be unless it was an 867 cpu) check out the Power Mac Firmware update 4.4.8 (http://docs.info.apple.com/article.html?artnum=120171)

Apparently this update helps control the fans, which are notoriously loud on some of the MDDs.
Read the description to see if it applies in your case.

Feb 23, 2010, 06:14 AM
I looked in properties, it is written 133 =\
Do not know about it.
This instruction will help?
or http://translate.google.com/translate?u=http%3A%2F%2Fwww.macbidouille.com%2Fniouzcontenu.php%3Fdate%3D2002-10-08%233610+&langpair=fr%7Cen&hl=en&ie=ISO-8859-1&prev=%2Flanguage_tools

Feb 23, 2010, 10:18 AM
You said you were running a dual 1Ghz. If it's a model #M8689LL the bus will be 167. If it's #M8787LL it will be set at 133. The latter is normally an 867 cpu.

From the article Passer le bus d'un G4 Bi 867 167Mhz (http://www.macbidouille.com/articles/89/page2)
It's possible to run an 867 cpu overclocked to around 1Ghz, and you can check if resistors R676, R678 and R677 are all there, but I doubt that's the problem.

If it is running with the dual 1.25 but is really noisy that could be due simply to the history of MDDs being notoriously loud. The problem was mitigated to some degree by the last MDD made, but yours would be the previous model.

It's been a while since I messed with the internals of Power Macs so I'm not current on them.

Feb 23, 2010, 12:07 PM

That's what you need to do.

Mar 2, 2010, 05:36 AM
I did everything according to instructions. removed the resistor R676, but still does not start with the DP and the SP is run and the properties says "bus speed - 133 Mhz"
what's wrong? =\

Mar 2, 2010, 09:52 AM
There is no chime with 1.25 DP, i guess? Only fan blast?
I'm sure on 99% that your Dual 1.25 daughtercard is DOA, cause it should start normally with your logic board, even without changing FSB freq (only with Dual 1.0 GHz and FSB 133 clocks).
This 1% i reserve for bent pin(s) in CPU socket (on daughtercard) - check it.
You can try PMU reset also. If it not helps, CPU is dead.

I did everything according to instructions. removed the resistor R676, but still does not start with the DP and the SP is run and the properties says "bus speed - 133 Mhz"

You done half of job. To run this lobo with 167 MHz, you should to install 167 MHz bus CPU (real or OC'ed - and at least PC2700 DDR ofc).
To OC your 1.0 CPU to 167 MHz bus, check this thread: http://aquamac.proboards.com/index.cgi?board=talk&action=display&thread=151 - you will find all what you need there.
I had done it many times, it's quite easy if you have any soldering skills. It's not any big OC, but always better than nothing ;)

Mar 2, 2010, 12:22 PM
What is now.
http://img695.imageshack.us/img695/1074/dscf0234.th.jpg (http://img695.imageshack.us/i/dscf0234.jpg/)
this is old SP 1 ghz
http://img176.imageshack.us/img176/3180/dscf0244.th.jpg (http://img176.imageshack.us/i/dscf0244.jpg/)
this new DP 1.25 ghz
http://img689.imageshack.us/img689/7757/dscf0247fr.th.jpg (http://img689.imageshack.us/i/dscf0247fr.jpg/)
that there is need to change?
http://img189.imageshack.us/img189/1204/dscf0253g.th.jpg (http://img189.imageshack.us/i/dscf0253g.jpg/)
http://img85.imageshack.us/img85/620/dscf0251y.th.jpg (http://img85.imageshack.us/i/dscf0251y.jpg/)
http://img191.imageshack.us/img191/7517/dscf0249v.th.jpg (http://img191.imageshack.us/i/dscf0249v.jpg/)

Mar 2, 2010, 12:57 PM
Here (http://aquamac.proboards.com/index.cgi?action=gotopost&board=talk&thread=151&post=7352) is FSB resistors location on 1.25 GHz single CPU module (valid also for 1.0) and my explanation.
Read carefully whole thread (starting from this post that i linked).
In last post of this thread i added links to chart of multiplier settings for MDD and single CPU clock resistors location.
Max what you can reach with working L3 cache with FSB 167 is 1.17 GHz. No need to bump core voltage.
Default multiplier of 1.0 GHz module is 7.5x (that refers to 133 MHz bus)
To get 1.17 GHz (7x multiplier) with 167 bus, you need to remove PLL2 resistor and set resistor (or bridge from solder) at PLL3 position. There are 2 columns of PLL resistors, HI and LO. They are located at the front of CPU card, on the right of CPU core. You only need to change those in column LO.

Mar 20, 2010, 08:22 AM
I overclocked single processor to 1.25 Ghz on 167 Mhz bus speed. seems the seller on ebay sold a dead processor =\
thx to all