Macintosh Centris 650


macrumors member
Original poster
Apr 2, 2012
Cincinnati Ohio
So I recently bought a Centris 650. While not a PowerPC mac I was too excited not to share this somewhere. I haven’t done much in the way of restoration except for some cleaning. Eventually I would like to spec it out on ram and vram, and probably a SCSI to SD. I’ve currently got it running a Mac OS 8.1 install off of a external SCSI CD drive. I also have an Ethernet adapter so I’d like to try some networking too. Maybe connect it to a few of my newer PowerPC Macs. I’d love any tips on this machine, or machines if this vintage, and any ideas for the future! Also for those interested I paid 35 bucks for it from an ancient professor trying to sell some lab equipment. It was used in a lab setting best I can tell. Had temperature data on it.


macrumors regular
Jan 13, 2020
I can't say I'm an expert on the thing, but it's a 68040, and it looks like you've already handled OS 8.1, which is what you need for large hard drive support. Mac OS 8.1 is the only 68k version that supports HFS+, and while it can't boot using HFS+ on a 68k, any other partition can use it as long as the boot partition is plain HFS.

A quick check says that this particular machine supports up to 138mb of ram, but my understanding is that these systems are extremely finicky about the particular ram they take. But take that last bit with a grain of salt since I've never upgraded anything 68k before.

You are in the position to run most 68k software, especially late era software. I'm a little jealous, my Performa 405 doesn't boot.
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macrumors 68040
May 28, 2006
Manchester, UK
IIRC they could be finicky as were the similar Quadra. It wanted to run the memory in interleaved mode to increase performance. So if the RAM wasn't matched pairs within the bank it got tetchy.

Nominally they were standard 80ns 72-pin SIMMS.


macrumors 601
Dec 19, 2004
It's a great machine. My first Mac was a IIvx. Which I did a Centris 650 motherboard swap about a year later. It flew with System 7.1. Since systems of that vintage aren't great for web usage. I'd say to consider running System 7.1 to improve performance and run some era appropriate software. Played many hours of Realmz, Flight Simulator, Battle Chess and King's Quest on it. Photoshop 3.0.4 ran well as did MS Office 3. Also Totally Twisted After Dark and Star Trek TNG screensavers are must haves.

Does yours have a 68040 CPU or is it one with a 68LC040 CPU?

If you want to add a CD-ROM. Try to get the caddy model and bezel for it. Not the tray loading and bezel. For that vintage feel. Although I suppose tray loading is more practical.


macrumors 68020
Jul 25, 2008
Central US
I had one many years back, but its actually one of the few machines I opted to sell. Kind of wish I'd kept it and parted with something else just to have a "Centris" in the mix.
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