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Looking for Information About the Apple High Performance Processor Card Model 1100


Active member
Hi folks,

Courtesy of a Trading Post thread, I've just learned of the existence of this processor card for PCI PowerMacs. A quick search online shows they're reasonably common and inexpensive, but I'd never encountered one and information seems nearly nonexistent. Every Apple processor card I've run into is marked with little more than a part number, and these cards are clocked at speeds that don't entirely gel with the 8x00 and 9x00 lines as far as I'm aware.

Does anyone have information about the provenance of these things? It seems unusual for a piece of Apple's hardware to be so poorly documented.



Well-known member
Those cards only came in the 8600/250(not sure), 8600/300, 9600/300 and 9600/350 and they won't work in any other machines.

They have 1MB of cache right on the CPU card. Apple slightly changed the pinout of the processor slot on those machines because the cache went from residing on the logicboard to the CPU card.

On the front of the card there's the CPU, cache controller, a tiny 256K SRAM for the controller to store cache tags and half of the 1MB cache...


and on the back we've got the usual... buck step down controller for CPU core voltage, clock generator, the other half of the 1MB cache, another SRAM for tag storage...

Also notice the resistor jumpers on the left to select between 250/300/350/400MHz CPU clock.




Well-known member
Here's some more info:

The jumpers on the back of the card with speed labels do absolutely nothing; they're just there for quick reference while actual setting of the PLL is done elsewhere on the card. Most were 300 or 350MHz; 400MHz cards were never officially shipped (if ever).

These cards were developed to use the 604ev Mach 5 processor, IBM's latest chip and the fastest of the 604 variants, capable of supporting up to a 100MHz bus. Of course, no Macs of that era could support a 100MHz bus, so they had to do some tricks: these were designed with what's called an inline cache, a high-speed cache mounted close to the processor, running at less than full processor speed but more than system bus speed. The large LSI-badged chip is multi-function, being both a cache controller and bridging the fast processor/cache bus (100MHz) to the slower system bus (50MHz).

When one of these cards is used this means that the 512k of cache soldered to the logic board of some machines is disabled, which I think is kind of a waste of money (why did they solder it anyway? They should've kept using modules) but good fiscal decisions were not Apple's strong suit in the '90s.