Getting a new MDD motherboard

MatthewLTL

macrumors 68000
Original poster
Jan 22, 2015
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Rochester, MN
A kind user on MR has mailed me a MDD FW800 167MHz motherboard.

Thing is my Processor is only the 133MHz 1GHz model, One user on here suggested it would indeed overclock to 1.25GHz. Is this true? Could i USE my current CPU or do i have to set the new board to the side when i get it and order me a 167MHz CPU?
 

bunnspecial

macrumors 604
May 3, 2014
6,716
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Kentucky
Because that's how the the multiplers work.
Intell,

I trust you implicitly on this stuff and assume that you've probably done exactly this at some point, but I'm having a bit of trouble following this also.

On a 133mhz FSB board, a 1ghz CPU is running at 7.5x. Assuming that the multiplier is hard-coded to the processor card(which I realize may not be a valid assumption) if that same CPU were transplanted to a 167mhz FSB board, it should run at 1.25ghz.

Are you saying that's not the case?
 

Intell

macrumors P6
Jan 24, 2010
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Inside
I don't remember what they downclock two. They downclock to the highest speed ratio attainable on the bus without going over their set clock speed.
 

MatthewLTL

macrumors 68000
Original poster
Jan 22, 2015
1,684
18
Rochester, MN
I don't remember what they downclock two. They downclock to the highest speed ratio attainable on the bus without going over their set clock speed.
I plan to get a faster CPU anyway (hence why I was after and am recieving a 167MHz FSB board). As long as you can assure me the MDD will physically boot with a 133MHz CPU in there that's all that matters at this point.
 

bunnspecial

macrumors 604
May 3, 2014
6,716
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Kentucky
LeopardAssist makes bypasssing the 867mhz check trivially easy-you literally just run the program and restart the computer into the Leopard installer. It's also not a lot more work to do it from Open Firmware.


As Intell says, PCI based G4s do require more work. I've been tinkering with one on and off for a few months(admittedly a G3 upgraded to G4, but in actuality nearly identical to the PCI G4), and still haven't been able to get there.
 

MatthewLTL

macrumors 68000
Original poster
Jan 22, 2015
1,684
18
Rochester, MN
LeopardAssist makes bypasssing the 867mhz check trivially easy-you literally just run the program and restart the computer into the Leopard installer. It's also not a lot more work to do it from Open Firmware.


As Intell says, PCI based G4s do require more work. I've been tinkering with one on and off for a few months(admittedly a G3 upgraded to G4, but in actuality nearly identical to the PCI G4), and still haven't been able to get there.
well the fact i see no difference in preformance for Leopard on my eMac with 512MB RAM and my MDD wiith 1GB i assume I'll see little difference in a underclocked CPU (Does this mean the CPU will run at cooler temps?)
 

LightBulbFun

macrumors 68020
Nov 17, 2013
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London UK
regarding the down clock feature if they down clock not to go over there rated speed then How dose Over clocking 1.42Ghz MDD modules work then? since all there doing is changing the multiplier in relation to the bus speed to attain a higher speed (which you say would actually down clock since the CPUs are not rated for higher?? unless theres something Im missing?)