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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: QuikSanz on September 29, 2016, 10:36:20 PM
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I'm curious, Can a ZII bus be doubled if if not using a Toaster. What may be the pitfalls of this. There must be some way to increase bandwidth to give lets say a Vampire better performance. A graphics card could benefit.
Chris
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I'm curious, Can a ZII bus be doubled if if not using a Toaster. What may be the pitfalls of this. There must be some way to increase bandwidth to give lets say a Vampire better performance. A graphics card could benefit.
Chris
Vampire sits in the CPU slot on an A2000, or in the CPU socket if you can cram it underneath the drive sled. It doesn't use a Zorro II slot.
Don't know about overclocking the bus, I think you're hitting limitations on the old Buster chip in the A2K (as well as probably numerous other components); it never had any revisions or updates like the A3K/A4K Buster chip did for improved performance. :(
See pic of Vampire installed in A2000 that I copied off Google+ a few days ago:
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I was thinking the rest of the chips may not handle this but this could reduce the "bottleneck" if it can be done.
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I was thinking the rest of the chips may not handle this but this could reduce the "bottleneck" if it can be done.
Pretty sure you'd get better performance using the onboard video of the Vampire board than any Zorro II graphics card. Zorro II slots are still useful for legacy SCSI boards/peripherals, sound cards, networking, etc., though. ;)
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Pretty sure you'd get better performance using the onboard video of the Vampire board than any Zorro II graphics card. Zorro II slots are still useful for legacy SCSI boards/peripherals, sound cards, networking, etc., though. ;)
If you have A USB card, sound card and net card in it the bus is waiting sometimes. forget the graphics card.
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Yes, the bus can be overclocked but then you would face a few incompatibilities with some Zorro II cards that rely on this old timing.
Just to name a few examples:
-The Elbox Winner Zorro IV busboard (a Zorro II busboard) had a fast Zorro II mode on some slots. The CyberVision 64/3D cards that were manufactured by DCE (not Phase 5) can take advantage of this feature and also the famous Deneb USB+flash rom card.
-The MacroSystem´s DraCo has five Zorro II slots that operate at twice the speed of the traditional Amiga Zorro II slots and can make use of most of the Zorro II cards that were made.
So yes, it can be done.
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-The MacroSystem´s DraCo has five Zorro II slots that operate at twice the speed of the traditional Amiga Zorro II slots and can make use of most of the Zorro II cards that were made.
So yes, it can be done.
Running zorro 2 at double the speed would involve doubling the speed of dma as well, which would also include fast ram on the cpu bus. By the time the double speed clock has spread that far round the A2000, you're running the risk of having to do something special to make it avoid hitting the cia/agnus/paula etc. You may hit problems with buster or the way the motherboard is designed. The former could be solved by creating a new buster chip, the later would require something like an "a2000 reloaded".
The draco just proves that you won't have too many problems with the cards.
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This is interesting.
Would it be possible to oveclock zorro bus without affecting amiga's mobo / custom chips?
Overclocking zorro bus would have 1:1 effect for a speed of rtg graphics. 3.5mb speed of zorro II is major bottleneck. Drago's zorro is not 2x faster. Speed is about a 4.5mb tells google.
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FWIW, there's some Zorro-II hacks for A3000/4000 super busters:
http://www.amibay.com/showthread.php?18537-SuperBuster-Zorro2-Speedup-Mod
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Drago's zorro is not 2x faster. Speed is about a 4.5mb tells google.
You should not always believe what Google tells you.
I have two DraCos at home and Zorro II slots can be run twice as fast. Of course this depends on the particular card you are using, because the card itself may be the bottleneck. :)
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Hmm, Would be interesting to have a switch to toggle the speed and check it out for software and card compatibility. If some things are picky you could leave it as a turbo button.
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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.
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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.
Did you ever look at running zorro-iii cycles on an a2000?
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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.
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because Super Buster is a downgrade for Zorro-II users.
Out of idle curiosity, how is it a downgrade? Is it because of all the DMA issues in the various revisions of the chip?
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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".
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@SpeedGeek,
I'd love to see that Schematic on Amibay but it won't let me see it, even after registering.
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Unfortunately, all the revisions and bug fixes were for Zorro III and Zorro II performance was never "Up To Par".
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.
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@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.
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It may take a few to days get full access to Amibay since new member registrations are approved by a staff member.
Still no access. Dead end.
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This?