dual 1.42ghz cpu in a dual 867mhz?

[supernova777]

presently my mdd is the 867mhz dual processor model.. i actually bought it for 35$ and spent the time to modify the fans to make it whisper quiet etc
if i was to upgrade the cpu, im wondering what options i have?
looking for low cost (duh) high performance! (ya!)

would it be compatible with a 1.25ghz single mdd original stock cpu? (going frm a dual to a single cpu)
would it be compatible with a 1.42 dual mdd original stock cpu from a fw800 mdd? (going from a fw400 model cpu-> fw800 model cpu)


http://www.everymac.com/systems/apple/powermac_g4/specs/powermac_g4_867_dp_mdd.html

quicksilver lineup
Power Macintosh G4 733 (Quicksilver) 733 MHz PowerPC 7450 (G4)
Power Macintosh G4 867 (Quicksilver) 867 MHz PowerPC 7450 (G4)
Power Macintosh G4 800 DP (Quicksilver) 800 MHz PowerPC 7450 (G4) x2
Power Macintosh G4 800 (QS 2002) 800 MHz PowerPC 7455* (G4)
Power Macintosh G4 933 (QS 2002) 933 MHz PowerPC 7455* (G4)
Power Macintosh G4 1.0 DP (QS 2002) 1.0 GHz PowerPC 7455* (G4) x2

mdd lineup
Power Macintosh G4 867 DP (MDD) 867 MHz PowerPC 7455 (G4) x2
Power Macintosh G4 1.0 DP (MDD) 1.0 GHz PowerPC 7455 (G4) x2
Power Macintosh G4 1.25 DP (MDD) 1.25 GHz PowerPC 7455 (G4)x2
Power Macintosh G4 1.0 (FW 800) 1.0 GHz PowerPC 7455 (G4) (cant boot os9)
Power Macintosh G4 1.25 DP (FW 800) 1.25 GHz PowerPC 7455 (G4)x2 (cant boot os9)
Power Macintosh G4 1.42 DP (FW 800) 1.42 GHz PowerPC 7455 (G4)x2 (cant boot os9)
Power Macintosh G4 1.25 (MDD 2003)

[Protools5LEGuy]

I will receive next month a MDD 867 too. Yesterday I searched a little and I can tell you...
MDD 867 has a 133 bus and you can change CPU module without mods only with 133 bus MDD, and the only model was a Ghz not dual cpu.
So you will need to mod 2 things
The motherboard needs to be taken from the box to unsolder something and the cpu needs to be modded to, but every 866 MDD should go 166 bus and the cpu unleashed to 166 you get a 1.067 dual with the same equipment (0$ cost) 
http://web.archive.org/web/20090301000742/http://bitsandpieces.info/Multipliers.htm

http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.macbidouille.com%2Farticles%2F89%2Fpage2&act=url
I think when you unleash the 166 bus (and use 333 memory) you can buy a copper heatsink from the 1.42 and a cpu for the 1.42 and have 1.42 on a FW400 with os9    But for now just unleash the 166 bus and overclock/unleash the 166 on the cpu as macbidoule .
Later we can go thru the overclocks over 1.42 from http://www.s155158671.websitehome.co.uk/watercoolyourmdd.html.
I am now in a point of love over Mac Os9 and powermacs that I think I am going to let the MDD866 be a MDD866 or pehaps go 166 but 0 cost for next 2 years. For sure without mods will continue to work 5 years more. I am not sure on how well can handle this pretty box 1.42 ghz with air cooling mods, but I will fall your steps in taking it to the 166 bus, because it is well know that all MDD can get 166 bus.

[Protools5LEGuy]

http://www.xlr8yourmac.com/systems/g4_mirrored_drive_doors/G4_MDD_CPU_Module.html There is more info
Also http://www.s155158671.websitehome.co.uk/aircoolingmddg4a.html

[supernova777]

yes i forgot to say, i dont want to stretch the boundaries of the machine far.. only safest 100% compatible upgrade option!
so like u said.. i should pick another cpu with the same bus speed of 133mhz?

[Protools5LEGuy]

If you don't want to stress (!) the motherboard in my use of MacOs9 I think for logic I would prefer Dual 867 over Ghz alone (I think is the only other 266 bus MDD), because logic benefits of dual processor but for Protools I would prefer the Ghz cpu because in os9 the second processor does nothing.
That been said and with no money limits I would send the MDD to a technician with soldering skills to make the board 166 compatible and would mount a 1.42 cpu with its copper heatsink. But this is too much money (I think) versus the performance you could get.
The 1.25 dual MDD cpu  and the aluminium heatsink are cheaper, but you still need to mod your motherboard to get 166 bus!

[supernova777]

yeah that aint gonna happen .. re: 166mhz bus mod...
im way to chicken to do that;) i screwed up a g3 once trying to upgrade its cpu....
no clue how..

[DieHard]

I have tried almost every combination of Power Mac G4 Motherboards & Processors (Yikes thru MDD)... I have even had a the pleasure of messing around with a few prototype G4 MBs that leaked from apple over the years

Single and Dual CPUs... as far as stock apple (non-3rd party upgrades) my 2 personal favorites are...

Quicksilver 933 (with a few fan mods)... Started out quiet (compared to MDD) and made really quiet, this baby has plenty of CPU cache, very stable for DAW Apps

MDD Firewire 400 (with a harder fan mods)... Started out Loud (even with Apple factory Pabst Lower Case Fan, and PS replacement done under warranty), and made very tolerable with further fan mods, this baby has plenty of CPU cache, Fast PATA IDE Bus, very stable and fast for DAW Apps with lots of plugins

Single vs Dual (I have personally noticed, and commented other times) that under Pure Mac OS 9 (obviously not classic) that there is NO benefit  using Dual Processor daughter boards, and in fact, single CPUs are more stable and preferred with some apps.

Mactron (like many others) like to over clock MDD 1.25 and get them up to 1.5 (with great success and stability)..

From the Web...

With PLL position it was very easy - they are described at the front of PCB, on the right. Only difference was the PLL4, so i thought that is equal to PLL_EXT, and i was right PLL's config table is exactly the same like DP modules on bitsandpieces.info. Little harder was CV resistors location. I compared resistors around voltage regulator on MDD's 867 DP daughtercard (which have the same voltage regulator like single 1.25 and 1.25 DP 2 MB L3 - LTC1709EG). Voltage table is also exact like 1.25 DP 2 MB L3 CPU. I have found adequate resistors on my 1.25 single module and quickly OC'ed it to 1.67 GHz with 1.65V with no troubles. So far it is stable, i had run few Xbench and Cinebench 2003 test, net surfing etc without hangs or kernel panics. Now i'm trying 1.75 GHz at 1.65V but my MDD freezes at getting about 40 degs C (weird, at 1.67 it gets about 43 degs C and no freezes) and i got one Kernel Panic at start. Maybe it requires higher voltage, 1.7 V or even more. I have uploaded pics of resistors position to Imageshack. I forgot to take screenshot at 1.67 GHz, but i uploaded one at 1.75 GHz.

http://imageshack.us/photo/my-images/299/g4mdd125singleresistorsvj5.jpg
http://imageshack.us/photo/my-images/183/ppc7455corevoltageif1.jpg
http://imageshack.us/photo/my-images/17/picture2js3.png

Notice, that i have not tested voltage config higher than 1.65 V yet, so if you are brave enough you have to do it at your own risk! If i will test higher setting, i will post it here.
P.S. Excuse me for my poor english
Update:
1.75 GHz is not stable, even at 1.7 and 1.75 V. It freezes even faster than at 1.65 V. I'm thinking, that the problem is cache memory, which cannot run stable at 292 MHz. Maybe someone of you will be more lucky than i am. Core Voltage resistors identification confirmed.

Regards
Adam

[supernova777]

i would like to know more about overclocking the mdd, is it hardware? or software overclock?
i wouldnt want to make any undoable modification

[Protools5LEGuy]

http://www.ebay.es/itm/CPU-867Mhz-Dual-Processor-Apple-PowerMac-MDD-G4-820-1310-a-CPU-Board-Warranty-/201010487017?pt=UK_Computing_CPUs_Processors&hash=item2ecd289ee9

Can you afford it? You could try overclock keeping 133 bus on the motherboard. Or buy another motherboard

http://www.ebay.es/itm/Apple-PowerMac-G4-Mirror-Door-MDD-Logic-Board-820-1476-A-630-4655-/321057619300?pt=UK_Computing_Other_Computing_Networking&hash=item4ac0867d64

Just buy spares and mod a motherboard for 166 bus or buy a 166 ready (More money).

Then a http://www.ebay.es/itm/Apple-PowerMac-Processor-1-25GHZ-CPU-820-1497-A-/181107462983?pt=DE_Elektronik_Computer_CPUs&hash=item2a2ad89347 or just the module for your heatsink http://www.ebay.es/itm/Apple-820-1472-A-PowerMac-G4-MDD-Dual-1-20GHz-CPU-Processor-Tested-Working-/131090262279?pt=CPUs&hash=item1e8596a907

It should be interesting to make research of any more info about the mod of the motherboard. It seems really easy and quick with the propper skills but not really clear thru the translation. Also is not clear if it is recommended to take the 867 overclocked to 1.067 and beyond or to 933 only. Most modder start with 166 bus boards and 1.25 dual cpus.

I think the voltages are important for overclock, but also is important the cache speed, with some cpus cache are easier to overclock than with others. Maybe 1Mb cache more/less overclockable than 2Mb ones. 

I readed somewhere (macrumors/xlr8yourmac) about a openfirmware hack to overclock "via software" just as there is a OF hack to install Leopard, something about bus speed or anything related, but never tested.

[supernova777]

http://www.ebay.com/itm/Apple-Processor-Module-for-Power-Mac-G4-1-25Ghz-MDD-2003-820-1497-A-661-2914-/370911060852?pt=CPUs&hash=item565c05a374

heres one 16 bucks.. single 2003 mdd cpu!