Formac ProQuadra 50 MHz 68040 Upgrade?

[Nathan_A]

What sorcery is this: https://www.ebay.com/itm/373428484553 ?

I grabbed the photos for posterity.

 

[jeremywork]

What sorcery is this: https://www.ebay.com/itm/373428484553 ?

I grabbed the photos for posterity.

It’s essentially the same thing as the cached version of the Sonnet QuadDoubler or NewerTech Quadra Overdrive, but on a PDS card instead of directly in the 68040 socket.

 

[Nathan_A]

I really thought I'd seen 'em all at this point. Your description makes sense. So the Quadra 900 here would normally be running its bus and CPU at 25 MHz, and this thing clock doubles the bus and runs the CPU at 50 MHz. Makes sense. It's like a 68040 DX2

Kind of neat that you can defeat the clock doubling in software to run it at the lower 25 MHz speed. Though I have no idea why you'd do that since it's then just the same as the stock CPU. Perhaps for the cache?

 

[Bolle]

There’s no cache on there. It’s just a 50MHz 040 sitting behind some bus buffers.
Formac built a similar card for the LC475 that goes directly into the CPU socket:

 

[jeremywork]

I really thought I'd seen 'em all at this point. Your description makes sense. So the Quadra 900 here would normally be running its bus and CPU at 25 MHz, and this thing clock doubles the bus and runs the CPU at 50 MHz. Makes sense. It's like a 68040 DX2

Kind of neat that you can defeat the clock doubling in software to run it at the lower 25 MHz speed. Though I have no idea why you'd do that since it's then just the same as the stock CPU. Perhaps for the cache?

It is pretty cool to be able to choose (especially for benchmarking purposes.)

Technically the other two reduce to 25MHz any time the CPU needs to communicate directly with the bus, but I don't think they can be manually disabled.

There’s no cache on there.

Oops, thanks.

 

[ArmorAlley]

There’s no cache on there. It’s just a 50MHz 040 sitting behind some bus buffers.

Did Motorola ever make 50Mhz 68040s or is it an overclocked 40Mhz 68040?