trag said:

I think the OP said this was in a Centris 650.  Didn't the Centris have a 25MHz bus?  The Quadras were pretty much identical to the Centrises but with a 20 to 25 MHz bump for the 610 and a 25 to 33 bump for the 650.

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OP says Quadra 650 @ 33MHz

As to whether a PDS CPU upgrade **needs** an extension/control panel or not, I had a conversation in which I was told that one of the early daughter board upgrades on the 128K/512K used some trick in bus arbitration to shut down the host CPU, but in that case, the upgrade has full access to all of the original CPU's pins.   So I could go either way.   Sure seems like the Turbo040 and such are active whether you load Daystar's software or not, but my memories are old and crumbly.

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Daystar's Universal PowerCache Install Manual says you've gotta install Power Central in the System Folder. Dunno, I've used several PDS Accelerators and Cache Cards from the 68000 on and all needed an INIT to shut down the native proc. to work. 2x CPU active on one I/O bus = BAD Juju, but this Card is definitely an odd duck.

ScanDump Box tearsheet search turned up bopkes. I've got various MW, MU & Byte Accelerator Review Articles from 91 - early 93, so nothing for the 650 and no products mentioned from Formac. No Formac listed in the Advertiser Directory of the May '94 PowerMac Intro, Macworld issue, nothing in the Star Ratings and I didn't see anything in the Mail Order House ads for accelerators.

If I find the intact Magazine collection, maybe something will turn up, but right now I got nuthin! :mellow:

edit: once again, ROM spelunking with TattleTech highly recommended. [] ]'>