Hi All,
I have the above machine running 2 gig Ram 500gig storage 10.4.9 and am looking for info on overclocking. Any help or just point me on my way will be sincerely appreciated

There is an (old) article from a site called Appletalk

MDD Overclocking Guide

The main link seems to be down, but it's cached under Google:

http://72.14.253.104/search?q=cache:...ient=firefox-a

Keep in mind if you've never overclocked a Mac before by desoldering/replacing resistors, don't do it on this one. Practice many times on old PCBs before taking the plunge on a nice Mac such as this

JB

Byrd,
Thank you for the info and doing it so quickly. Many years ago I chipped an LC111
from 25 to 33 MHz now I'll be more carefull but I still have the LC and it still works.

Cheers
Mike

hi and sorry my bad english
i have 1.25ghz mdd fw800
default jumper settings is like first table

now i have jumpers like third table.
about this machine shows 1.58ghz now and its unstable
so how i get this 1417mhz

(corrected personal error)

Here is one shamelessly ripped off from bitsandpieces.info (now seemingly defunct). The multiplier codes are valid for all PPC74xx series CPU's.

Thanks for posting the jumper settings marco007 - welcome - where are you from?

Seems a lot of info regarding MDD overclocking is down.

JB

I would be a bit wary of overclocking the MDD models only because of the common knowledge that they are prone to overheating already without cranking them up a notch or two. Thats one of the reasons why they are so noisy.The fans are working hard to get the temps inside lower. There are lots of threads both here and on other forums devoted to cooling these macs down via fan mods . By all means overclock them if you are willing and able but just be advised about the extra heat this may generate.
Stewie

Stewie is correct. However - with application of thermal gel and a copper heatsink, you can safely overclock the 1.25s to 1.42s and they will run basically identically to the stock 1.42s. The FireWire 800 Dual 1.25 models are apparently great for overclocking.

However, as Stewie mentioned, they are horrible for heat. If you're running in stock config, I'd be wary about what bits and pieces you put in there. Have a look at some of the cooling mods, it may require for you to put a fan in the ATA100 vertical HDD bay limiting you to 1 ATA100 drive in this location. The front drives are on the ATA66 bus.

So - overclock with a decent cooling upgrade plan. Its awfully important with the MDD.

I found a still working link to the guide I ripped the above table off from. This should not be seen as encouraging people too attempt it.

http://homepage.mac.com/paul74/Multipliers.htm

PS. What the others said too. Attempt this at your own peril.

Overclocking will only ever cause more heat if you have to push the cpu voltage up, this is a common thing to do because if you push it a little and it becomes unstable, pushing up the voltage slightly can get rid of the issue, but it causes more heat.

Quote " So - overcock with a decent cooling upgrade plan. Its awfully important with the MDD."
Ha . That would be one seriously ugly Mac , A_E.
Haaa Haaaa . You've just made my day. Are you trying to turn this thread into Inappropriate Moday ?
Stewie

I have a PCI slot cooler and a 72mm fan cable tied onto the back of my tower, so from the front and sides (since you can't even see the back without moving over my desk) my fans are invisible. Not to mention a copper heatsink and better thermal gel doesn't exactly leave big marks on the outer housing of the G4 towers (well, not that I've seen). Neither does the additional internal fan in the ATA100 drive bay. Perhaps you have some odd ideas about how to cool computer cases...if so, I'd be interested to see.

Two 72mm exhaust fans cable tied onto the back of the case (behind the cpus) and running on 7v will make the PowerMac run much cooler and will not increase noise by any amount I've noticed. Also, a good idea is to update the PSU fans and also to remove the plastic panels on the back to open the back up to better airflow. None of this will be visible from the front or sides (except for the two black boxes protruding from the back from the profile view), and will assist in cooling the system substantially. I've dropped about 0.7 degrees just with the single 72mm, I'll grab a second one when I have the cash. I advise it - especially if you're overclocking.



Also, to linux_insidev2...what is your point? I mean, I understand your comment and it was completely valid, but what was its relevance to my post? I said the 1.25 will run like a stock 1.42 when overclocked to 1.42 - identifying that it will run hotter. The CPUs are very similar, and the 1.25 will overclock easily and happily to 1.42, its reasonably well documented. The 1.42s up to anything higher is a different story. They are most probably the same chips off the same production line methinks, with different clock frequencies added. Anyway - that was my point...a midcommunication methinks

AE, stewie wasn't having a go at you but rather having a chuckle at the typo. The actual post was good.

usually adding more fans does require cutting up the case to make room,
Remember that if you want to blow air out you need to suck just as much in, there's not that many places in a powermac to ventillate.

Also remember that if you push air into the machine, have some fans extract the air too so that hot air doesn't pool up.
You don't want to count on the PSU fan to extract the heat because the PSU fan is there to cool the psu, pulling hot air through your PSU is not advisable.

0.7 Degrees is pretty small, you ideally want to be dropping temps several degrees by adding fans from 80mm up to 120mm with the 120's being quieter.

Hahaha, I can laugh at that too! I didn't even notice :P

Maybe I will go and edit that...