Is it possible to upgrade a eMac G4 CPU to a 2ghz G4?

[Angelgreat]

Hello, I'm thinking about getting a eMac 1.25 or 1.42, but I was wondering if the CPU can be upgraded to a 2ghz G4. I know it's soldered on directly, but would it be possible to put a 2ghz G4 in it's place? That would be cool to have a fast eMac while also booting into Mac OS 9 and 10.5 Leopard.

 

[alectrona2988]

You can overclock a 1.42GHz eMac to 1.92GHz. I'll do a writeup someday. Note that the 1.42GHz eMac will not support full graphics acceleration under (a modified) Mac OS 9.

As for the 1.25GHz models, your mileage will vary. I have a 1.25GHz eMac with an original PowerPC 7447 (NOT the 7447A or B) and that can only go up to 1.42GHz. The A models can get to 1.5GHz and the B can get to 1.67 without a vcore increase, although 1.25GHz eMacs with the 7447B chips are incredibly sparse. One 1.25 board I know of has a 7447B and is the 820-1798-A. I have one overclocked to 1.67GHz.

 

[Nathan_A]

You can overclock a 1.42GHz eMac to 1.92GHz. I'll do a writeup someday. Note that the 1.42GHz eMac will not support full graphics acceleration under (a modified) Mac OS 9.

Interesting. I'd be curious what that takes to do and how reversible it is. Does the system actually detect the correct CPU speed?

 

[demik]

Yes, but you need to be good at BGA soldering. Some people did similar upgrade in PowerBooks

 

[Daniël]

Interesting. I'd be curious what that takes to do and how reversible it is. Does the system actually detect the correct CPU speed?

No, PLL resistors set the multiplier for the CPU, which is how you change the clockspeed. As for 2GHz CPUs, I'm not 100% sure if 7448 CPUs came in that speed, but they certainly can clock to that with relative ease, especially in the eMac's massive cooling system. That said, I don't remember if dosdude1 et al figured out how to get those to work with the 7447-based eMac BootROMs.

 

[Angelgreat]

Couldn't we just add 2ghz 7448 G4 to a eMac or a iMac G4 and then overclock it?

 

[Cory5412]

The main thing adding a faster 7448 over the stock 1.42GHz chip would get you is 2GHz without needing to drive the chip too far out of band for what it was designed for. It sounds like the main limitation with the 7448, in addition to "literally soldering it on" which requires time and skill and equipment, is whether the firmware supports it or can be patched to allow it.

Just as a general sidenote, I love that there's love for eMacs developing. I wanted one when they were new and I'm organizing wit a friend to get one whenever I can get out their way, and I think in a very real sense they're great as a pre-ugpraded iMac with some better choices (e.g. trayload optical drive, 3 USB ports, faster networking, better graphics, better screen, better internal structure, etc etc.)

 

[3lectr1cPPC]

Just as a general sidenote, I love that there's love for eMacs developing. I wanted one when they were new and I'm organizing wit a friend to get one whenever I can get out their way, and I think in a very real sense they're great as a pre-ugpraded iMac with some better choices (e.g. trayload optical drive, 3 USB ports, faster networking, better graphics, better screen, better internal structure, etc etc.)

Yes! I love my eMac! Unfortunately just about everything I could use it for could be done better by my G5s (mine can't boot OS 9) so it doesn't see much use, but I always feel bad about not using it more. They're super underapreciated machines that are great on OS X. They're pretty darn reliable too, besides the few that had failing graphics and bad caps. They're certainly better in reliability than iMac G3s. Not to mention that they have the best CRT Apple every put into a Mac. Such a cool machine.

If you can find one for cheap, I can't recommend them enough as a starter machine. The eMac was my first PowerPC mac!

(My Specs: 1GHz SuperDrive w/ AirPort Extreme, 1GB of RAM, Tiger & Leopard)

 

[CC_333]

I wanted one when they were new and I'm organizing wit a friend to get one whenever I can get out their way

That wouldn't be me, by chance?

I like the eMac. I had the following firsts on a 700MHz example at a friend's house:

• First time burning CDs
• First time playing with Photoshop (7.0.1)
• First experiences with Mac OS X (10.1.4)

It was also the first Mac I'd used that had more than the 10 GB of disk storage and 128 MB of RAM my iMac had at the time (vs the eMac's 40 GB and 512 MB, respectively).

My friend gave it to me when it died, and despite much effort, I was never quite able to get it working 100% (I'm fairly certain the analog board was failing, but I didn't have the wherewithal at the time to repair it), but I since acquired another one or two functional ones, so it worked out.

c

 

[Cory5412]

That wouldn't be me, by chance?

If you're holding one for me, I forgot and I apologize!

My own eMac experiences are limited to some of the ones we had at school. I got a cap-death /1.25 from school surplus when I was a student at the local university, but this was before recapping was common on the vintage Mac scene and I have even less of the ability/energy/space to do it then than I do now so I tossed it at the time.

Compared to Mac minis and PowerMacs, the analog and power boards is going to be the bummer thing longer term, but eMacs do have video output so it should be possible to power the board and run it with an external display.

I'll probably post something when I do a norcal trip and see if anyone wants to say hi, though!

 

[CC_333]

If you're holding one for me, I forgot and I apologize!

No worries! This was a couple years ago, and Many Bad Things have happened in the world at large since then (which, as I recall, caused you to cancel a roadtrip you had been planning at the time), so multi-day roadtrips to get old Macs haven't been a particularly great Idea.

Anyway, with regard to dead/cap rot-inflicted eMacs, I have an empty eMac case, and I've had this idea for a few years now wherein I'd put an LCD in place of the CRT (the eMac's front bezel, being designed for a flat CRT, is a natural fit for an LCD, other than the fact that the opening is an odd size (17" is just a bit too big unless I were to trim back the bezel, but I bet a 16" panel would work quite nicely with the bezel as is)), and then sticking some other kind of computer (such as a Mac Mini or, given that there's lots of room, a micro ATX PC motherboard) inside.

Anyway, totally let me know when you're passing through, and we can arrange a time/place to meet up!

<tangent>
After the past two years being so dismal and depressing, I expect next year to be probably more of the same, but less intense with a few more signs of hope that there will once again be a normal that resembles 2019, insomuch as we can meet up with neither restrictions pertaining to nor fear of contracting the Plague.
</tangent>

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