We help IT Professionals succeed at work.

We've partnered with Certified Experts, Carl Webster and Richard Faulkner, to bring you a podcast all about Citrix Workspace, moving to the cloud, and analytics & intelligence. Episode 2 coming soon!Listen Now


Upgrading a Mac Centris 650

Medium Priority
Last Modified: 2013-11-17
I have a Centris 650 running at 32 mHz with a coprocessor.  I am looking for:

1) A PowerPC upgrade (either a new logic board that fits in a Centris 650 (I heard a PowerMac 7100 board will), or a processor card that sticks in a slot (like a PDS slot)

2) something like a Sonnet QuadDoubler (if it has a built in coprocessor thats okay...) ie double my 32 mHz to 64

If responding to the logic board replacement be certain to include all the boards that will work: (ie 7100, 8500, 6500)

I will assume that all upgrades mentioned at Mac OS 8 compatible....

Any and all suggestions welcome, send email to:
Watch Question

It is said that Powermacs created by upgrade, as well as the 100 series Powermacs won't run OS8.

So while it MAY be possible to swap out the logic board with a 7100 (and I'd be sure to compare the rear ports VERY closely before I bought one) the 7100 won't do OS8.

You want to run OS8 you'll have to get a native-born, PCI-based Power Mac. Sorry.


tekmo...thanks for pointing out that non PCI PowerMacs will not work for OS8.....however you didn't specify any upgrade chips or PCI PowerMac logic boards that will work for me.  As this was the entire intent of the question....I've rejected your answer.

Okay. Let's try again.

No-there is no PowerPc processor card that fits in a Centris PDS slot.

No-you can't put a 7100 logic board in your Centris box unless you replace the bottom case too. And it won't run OS8.

No-an accelerator will not make your Centris run OS 8, but it will probably accelerate the speed at which your processor will die. You don't get a speed gain without sacrificing something. Newer Technologies has something called MacClip. Your part is #7MC040-SC. Check with them for price.

If you want to give the Centris a little goose you can get about a 10% speed gain by interleaving your memory.


tekmo....I've been getting very contradicting info from official Apple resellers.

1) They say a PowerPC 7100 will run MacOS8....thus if I put a PowerPC 7100 logic board in my Centris....it will run MacOS8

2) They say any 68040 Mac will run MacOS8.

3) The QuadDoubler will work in my Centris....(just a speed increase)...but with it...I can run MacOS8 as well.

I don't know what to believe!
NONONO! that won't work! it is like a saquare trying to be put in a circle! For that money you spend on upgrades you can buy a low grade powermac! or better.

Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts

The Centris 650 had 3 options for a PowerPC upgrade and all are no longer supported products.

1) Apple made a PDS card with a 60MHz 601 PowerPC processor and 256k cache.  It was going for around $650.00 on an academic plan and went along with the very first release of desktop Power PCs...and therefore not much of a bang for the buck.

2) Apple offered, for a time, to take back the Centris/Quadra desktops and replace the Motherboard with a new 6100 or 7100 depending on whether you had the 650 or Quadra 840AV

3) Daystar made a NuBus card that ran an 80MHz 601 processor with 1 Mbyte cache, and it was expensive (> $1,000). I recently saw one in comp.sys.mac.wanted being offered for $300.00, probably  a good deal if you're unable to spring for a new machine

I have seen a 180 mhz for lees than a thousand. A 32 mhz is just too small to run even samll programs at a fair speed you just can't keep adding things to make it a little faster buy a cheap mac or macclone.


Thanks that did it!

Your welcome!
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.