Classic Bus overclocking?

[SpeedGeek]

FWIW, there's some Zorro-II hacks for A3000/4000 super busters:

http://www.amibay.com/showthread.php?18537-SuperBuster-Zorro2-Speedup-Mod

The above hack was done to get Zorro-II performance back to normal because Super Buster is a downgrade for Zorro-II users.

BTW, there are very few Zorro-II cards which could support a 2x overclock and most will fail without some extra logic to add wait states to a Zorro-II cycle.

[SpeedGeek]

Did you ever look at running zorro-iii cycles on an a2000?

No, the Zorro II bus is a 68000 protocol (24/16 bit) bus and Zorro III is a proprietary (32/32 bit) bus.

If you want to design a new GBA2000 mobo with a base 68030 CPU module then you could add Zorro III support but Commodore made the A3000 because it was cheaper than an upgraded A2500.

[SpeedGeek]

Out of idle curiosity, how is it a downgrade?  Is it because of all the DMA issues in the various revisions of the chip?

This is explained on the Amibay thread and also here:

http://www.amiga.org/forums/showthread.php?t=56277

Unfortunately, all the revisions and bug fixes were for Zorro III and Zorro II performance was never "Up To Par".

[SpeedGeek]

@SpeedGeek,

I'd love to see that Schematic on Amibay but it won't let me see it, even after registering.

It may take a few to days get full access to Amibay since new member registrations are approved by a staff member.

I saw a video recently where Dave Haynie says  that Zorro III was just him and it wasn't something that management were  asking for, so there wasn't any resources allocated to it. You're lucky  it even works a little bit.

Yes, and he also said Zorro III wasn't finished for the A3000 release because "Getting Zorro II Up To Par Was Tricky". Maybe he did the best he could with the time and resources he had. You can blame Commodore management (again) if you like but that doesn't help Zorro II users at all.