#Old CBM 68020 boards?
16 messages in this thread
Does anybody know if the old CBM 68020 accelerator boards are still
available (who sells them/how much) ??
– via Whap! (from Southern Illinois)
Jim,
The 68020 accelerator board (A2620) is no longer made. Can only buy them
used.
The 68030 accelerator board (A2630) is the current accelerator available
from CBM. Should be able to get one from any CBM dealer. Don't know the
price.
73, Kelly
Thanks for the info – hopefully, I can snag an A2620 somewhere. The '30s
and '40s acclerators are 'too rich' for my bank account!
– via Whap! (from Southern Illinois)
i think you'll find the 020 is just as fast as an 030 at equal clock
speeds, anyway. except for the MMU (and slightly larger cache) I never
understood why folks paid such high prices for 030s. Now the 040 is
another story entirely -FAST math right on board.
reply If the 020 is paired with a 68851 PMMU, as with the A2620, you incur
a one wait state penalty for the address to translate through the 851. The
030 does not incur this delay. The 030 also has a data cache which when
properly enabled, allows a typicaly speed increase of over 50% in most
benchmarks. At the same clock speed, the 030 will blow any 020 away. The
only time your claim even comes close to being true is when the both have
only 16 bit memory to talk to.
-Greg Tibbs
The 040 has only hardware multiply, add, subtract, and divide. All other
FPU instructions have to be implemented. Many of the transendental
functions are 30% slower than an equivalently clocked 030/68882
combination.
Change All other FPU instructions (of the 040) have to be emulated, not
implemented, or implemented in software. 😉 -Greg
Excuse me for jumping in like this… but you guys seem to be talking about
just the kind of stuff I need to know about! What would you think of
upgrading an A2620 board with a 25MHz 68882? Would this be close to an
030/68882 board for a number cruncher like Imagine? I can't afford another
accelerator and was wondering if it would be worth spending a couple
hundred bucks on a faster FPU instead.
Robert Fisher
If the software uses the FPU, it will see a performance increase. If not it
won't. I would think you might get as fast as 75% of the 030/68882 in some
situations, but if you get where the 68882 is always waiting on the 020 to
complete its work, then the performance will me much less. As they say:
you're mileage will vary… !
-Greg
– via Whap!
Well, the only program I'm really interested in speeding up is my ray
tracing program. Everything else runs fast enough for me with the 020. It's
all those floating point calculations that keep my machine crunching
through the night!
Robert
you'll be surprised how close the 2620 board is to a similar speed 030/882!
the 882 isn't that much faster in most real cases and the 030 isn't any
faster at all. it just has an mmu and a bit more cache. the 040 is the
only real power development since the 020. if you can get a good buy, go
for it!
Well, I went for it. Wyle Electronics has 25 MHz 68882 chips for about $95.
If I can manage to solder the 25 MHz oscillator onto the board without
screwing anything up, then I'll have firsthand knowledge on the performance
of an upgraded 2620 board by midweek!
Could you please post the address/telephone for Wyle Electronics…
That seems like a pretty good price.
Course I guess I should wait til you post your results!
..Bill 😉
Bill,
I'll try to remember to look it up next week. It's an 800 number in
Santa Clara, CA. It was kind of a pain setting up an account with
them…something about Motorola's paranoia and exporting their proprietary
technology to Iraq or some such thing!
Whatever…!
In any case, I should have the 68882 in my anxious hands shortly
after SuperBowl Sunday. I'll let you know if I've just blown $100 or if
it's all worth it!
Robert
Daniel, I don't know the in's and out's of it, but my 25mhz 030 (with 32bit
ram and math chip) is about four-eight times faster than the 14mhz 020
(also with 32bit ram and math chip) CSA board I had earlier. I remember
running timing tests when I originally upgraded. On comm'l type software
(tracers and such… shoot, I probably timed a FractPro render as well 🙂
Isn't the 040 on-board math non-transcendental? How does it perform on
your FractalPro stuff that uses those functions? (or maybe my info is off)
–jp–seattle–
I agree that the 040 boards are more worth their money than the 030 boards,
but they are both too expensive for me. An "old" 020 board, right now, will
fit the bill quite nicely. If I ever "strike it rich", I will definately
latch onto a 68040 board with LOTS of memory, but I haven't hit the "pot 'o
gold" yet.
– via Whap! (from Southern Illinois)
Not to my knowledge, Jim. I have not seen them offered for quite a long
time. Perhaps someone else will know.
Betty