Easy 68010 question...

[spirantho]

WHDload removes the copy protection so it will work fine that way. You just can't boot the disk

[RobertB]

Is there ever going to be something like an ACA500 produced?

I'm waiting for the Zeus68k to be on the market.  See http://eab.abime.net/showthread.php?t=65047

Then I'm buying,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug

[Thorham]

68020 is exactly the same as 68030 with its datacache chopped off.

That's not exactly the case. The 68030 can be clocked higher. Probably the highest clocked 68020 accelerator you'll find is a 28 Mhz one.

Without any datacache the speed of the processor gets crippled.

Of course, but not that much.

Its better to get a proper 68030.

A 68020 based accelerator is perfectly fine, because you'll still see a great performance enhancement, simply because the instructions run faster from the instruction cache, and the higher clock speed.

The 68020 could be a nice and cheap alternative to the 68030.

[ChaosLord]

Of course, but not that much.

move.l (A0),D0 ; Speed zooms on 030 but 020 has no datacache so it has to sit around all day waiting for the RAM to cough up the data.

Those sorts of instructions happen all the time.

A 68020 based accelerator is perfectly fine, because you'll still see a great performance enhancement, simply because the instructions run faster from the instruction cache, and the higher clock speed.

The 68020 could be a nice and cheap alternative to the 68030.

A 68020 is a 68030 that is missing its tiny 256 byte datacache.  So there is no logical reason for it to be cheaper.  It costs the same amount of money to make an 020 as an 030 for decades.

But if someone wants to sell him an old used cheap one for $5.00 with onboard ram then sure its a good deal then.   I would even go as high as $7.00 or $8.00 possibly.

[psxphill]

move.l (A0),D0 ; Speed zooms on 030 but 020 has no datacache so it has to sit around all day waiting for the RAM to cough up the data.
 
Those sorts of instructions happen all the time.

Only when the data has already been cached though, otherwise it's just as slow. It's only got 256 bytes of data cache & most software will have a larger working set than that.
 
There is no doubt that a 68030 is better than a 68020, but in an a500 it might be a bit of a waste. I had a 28mhz 68000 accelerator for the a500 and that was pretty good.

[ChaosLord]

For 3D gaming the 030 is better than 020.  For example the framerate in Stunt Car Racer is better.  Amiga has hundreds of 3D games that benefit from every ounce of faster CPU power.

256 bytes datacache is tiny, puny and pathetic but its still infinity times better than 0 bytes datacache on 000, 010, 020.

Of course the copyback datacache on 040 and 060 is massively better than the primitive write-thru cache on 030 but the OP would have to spend actual $$$ to get one of those.

[Thorham]

A 68020 is a 68030 that is missing its tiny 256 byte datacache.  So there is no logical reason for it to be cheaper.  It costs the same amount of money to make an 020 as an 030 for decades.

You're forgetting that '030s can be clocked twice as high as '020s

But if someone wants to sell him an old used cheap one for $5.00 with onboard ram then sure its a good deal then.   I would even go as high as $7.00 or $8.00 possibly.

You know that's not going to happen. A 28 Mhz '020 accelerator is worth MUCH more than that, and is actually a fine accelerator.

Only when the data has already been cached though, otherwise it's just as slow. It's only got 256 bytes of data cache & most software will have a larger working set than that.

Indeed.

For 3D gaming the 030 is better than 020.  For example the framerate in Stunt Car Racer is better.  Amiga has hundreds of 3D games that benefit from every ounce of faster CPU power.

Undoubtedly, but I don't think the frame rate is much higher on an '030 that's clocked the same. Seeing how '020 accelerators used to be cheaper than '030s, they're still not bad.

256 bytes datacache is tiny, puny and pathetic but its still infinity times better than 0 bytes datacache on 000, 010, 020.

It's indeed way too small. Too small to be of much use in many situations, and lack of such a small data cache isn't infinitely worse than having one. It would be different if it was, say, 4K.

[Lord Aga]

Isn't 030 also a process shrink ? So it's able to clock much higher. Maybe also cooler and uses less power ?

[Karlos]

The 030 isn't the same as the 020, though they are, from a user mode, more or less equivalent. Along with the datacache, the full 68030 also has an MMU on the die, which no 68020 has.

[ChaosLord]

The 030 isn't the same as the 020, though they are, from a user mode, more or less equivalent. Along with the datacache, the full 68030 also has an MMU on the die, which no 68020 has.

Good point.  I was thinking from a "writing code perspective".

The MMU is good for debugging, filing bug reports and running emulators like those awesome Mac emulators.

Its a shame that Motorola went to all that trouble to make us an MMU and then so many ppl refuse to buy it / use it.

[Karlos]

Don't forget the primary use of an MMU - to allow virtual to physical mapping of memory and all it implies.

[freqmax]

If Amiga had made use of an MMU then we could have somewhat less risk of bad things happening when running software.
Otoh, virtual memory tend to increase the number of clock cycles per instructions asfair?

[ChaosLord]

If Amiga had made use of an MMU

Amiga does make use of MMU.

 then we could have somewhat less risk of bad things happening when running software.

We have that when you run MuGardianAngel.

[psxphill]

Along with the datacache, the full 68030 also has an MMU on the die, which no 68020 has.

No, but it's 68851 compatible. So a 68020 + 68851 is equivalent. The 68030 works out quicker when using an MMU though because of that. The 68030 also supports a faster bus than the 68020 and it can be clocked faster.
 
All these variables make the 68020 vs 68030 comparison much more complicated than saying the 68030 is better than a 68020.
 
The quickest 68030 board could make a huge difference over the quickest 68020 board. But at what cost? A bad 68030 design compared to a good 68020 design might make it hard to justify spending more on a 68030. So unless you have two boards in front of you and can quantify the difference in performance then it's a pointless discussion.
 
Personal circumstances also play a part. Will you use the MMU & will the software you want to run benefit from the data cache.

[ChaosLord]

All software benefits from datacache.

[Karlos]

All software benefits from datacache.

Not all software. For some, it's an absolute poison