Zorro 3 Bus Speed

[trekiej]

Wikipedia says it is 150 MB/sec, I assume theoretical.
What do you think?
Did any card ever use that close to that much bandwidth?

http://en.wikipedia.org/wiki/List_of_device_bandwidths

[bbond007]

Wikipedia says it is 150 MB/sec, I assume theoretical.
What do you think?
Did any card ever use that close to that much bandwidth?

http://en.wikipedia.org/wiki/List_of_device_bandwidths

http://en.wikipedia.org/wiki/Amiga_Zorro_III

Although the Zorro III bus has a theoretical bandwidth of 150 MByte/s (32-bit x 37.5 MHz), the real transfer speed between the system and a Zorro III card is less than 20 MByte/s due to the limitations of the Buster chip. This is also the limiting factor with PCI expansion boards like e.g. Elbox Mediator PCI or the Matay Prometheus PCI (about 12 MByte/s PCI to 68k-system). DMA transfers between two Zorro III cards (or PCI cards on an PCI expansion board) can be much faster.

[Damion]

Wikipedia says it is 150 MB/sec, I assume theoretical.
What do you think?
Did any card ever use that close to that much bandwidth?

http://en.wikipedia.org/wiki/List_of_device_bandwidths

With Buster 11, writing to a PIV (for example) is just under 10MB/s. In practice, I doubt you'll get anywhere near 20MB/s.

[Matt_H]

Buster is a prime candidate for modernized FPGA replacement. I hope Jens Schoenfeld or the Natami guys are working on it.

[HammerD]

Buster is a prime candidate for modernized FPGA replacement. I hope Jens Schoenfeld or the Natami guys are working on it.

Would it be possible to put a drop-in replacement for buster to

1) fix stupid bugs
2) make it auto-magically faster?

[Matt_H]

Would it be possible to put a drop-in replacement for buster to

1) fix stupid bugs
2) make it auto-magically faster?

From my non-technical understanding, yes. But Michael Böhmer of E3B would know with more certainty.

[Effy]

I remember that somebody made his A4000 a lot faster by downgrading the crystal of the motherboard to something like 27 Mhz or so and that did speed up the fps of Quake a lot, though normal motherboard things screwed up so he could only use this trick when using the gfx card and soundcard ....

[bloodline]

From my non-technical understanding, yes. But Michael Böhmer of E3B would know with more certainty.

With the usual trouble finding 5V tolerant FPGAs...

[alexh]

No-one is going to make one. It is not economically viable.

[billt]

Would it be possible to put a drop-in replacement for buster to

1) fix stupid bugs
2) make it auto-magically faster?

I've imagined exactly this before. Since Jens has the ability to actually do it, I'm hopeful that he or someone else who can, does. Is there enough market for it to make commercial sense? Not sure about that part...

For socketed Buster motherboards, yes, you can do those two things. Think something like the 2MB Chip Ram things that fit into the Agnus socket. perhaps even have something else in the FPGA if there's room and something useful to do.

For SMT Buster motherboards, you need something to attach the FPGA thing to. And you can't disable Buster like you can disable 68000 for accelerator systems, you'd need to remove the SMT soldered Buster chip and put a socket in its place. Doable, but not necessarily anyone at home installing that.

[billt]

With the usual trouble finding 5V tolerant FPGAs...

Put some level shifters on the PCB, a voltage regulator perhaps. Not a problem.

[Zac67]

I remember that somebody made his A4000 a lot faster by downgrading the crystal of the motherboard to something like 27 Mhz or so and that did speed up the fps of Quake a lot, though normal motherboard things screwed up so he could only use this trick when using the gfx card and soundcard ....

... probably just slowed down the stopwatch for measuring the fps... The 28 MHz clock drives the chipset and the CIAs housing the system timers. If the CPU clock doesn't change (like it wouldn't in a 4000) it appears to run faster because of the time warp.

I'd overclocked my A500 back in '89 with a 32 MHz crystal. It did work nicely but my RGB monitor was literally screaming from the increased scan rate - and the integrated clock was running quite fast.

[trekiej]

cool

[Tension]

No-one is going to make one. It is not economically viable.

But surely nothing is economically viable in the Amiga world these days.

Some people will pay whatever it costs.  The others could never afford it.

[Crumb]

I'd overclocked my A500 back in '89 with a 32 MHz crystal. It did work nicely but my RGB monitor was literally screaming from the increased scan rate - and the integrated clock was running quite fast.

Zorro3 can be overclocked to 33Mhz too but real amiga video and sound will probably suffer.