mwm@pa.dec.com (Mike (My Watch Has Windows) Meyer) (05/28/91)
In article <1991May22.075230.28400@athena.mit.edu> ringo@athena.mit.edu (John L. Kimble) writes:
Hi there,
I recently bought an A2000HD. Although I'm fairly sure that I can't
afford buying a 68030 microprocessor for at least a year, I was
wondering if anyone could offer some advice as to possibly picking up
a 68010 or 68020 as a "quick fix."
How are the speed improvements? Any ideas as to $$$ costs?
Any particular compatibility problems to be wary of?
A 68010 is cheap (~$10), and is pretty much just a swap, as its pin
compatible with the 68000. I found about a 5% improvment on some
random tests; if you code for the '010 specifically you might see as
much as 25%. I don't recommend this if your machine is still under
warranty; it just isn't worth it.
Costs for cards 32 bit cards without 32 bit memory start at around
$400 (excellent street price) and go up from there. If you get a CPU
slot card (recommended), it's more like $600. However, you don't get
much of a win from an '020 or '030 unless you've got 32-bit memory in
the system. With an asynch '020 or '030 board, the best you're liable
to see for an applications is 50%. With a board running in synch with
the Zorro bus, you might see a 100% improvment.
Adding any 32 bit memory roughly doubles the price - you've usually
got to do a second card, plus memory interface. However, most
applications will do much better than that 100% best without memory,
even on a slow '020 with a losing application. 200% would be at the
low end, and 500% would be the high end on an '020.
The above numbers are for "general purpose" type things, derived from
benchmarks, running editors and C compilers. If you've got something
specific you want to go faster, you might see much better numbers. An
extreme but common case is ray tracing. That's FP intensive, so an
'020 card with an '881 will be a major win, even without 32-bit memory.
Compatibility issues: Any well-written software should run on all
these processors without any problems. The A2500 has been around long
enough that there's no excuse for software not working on turbocharged
amigas. Some early applications break on any of them by using
protected mode instructions. Some games have processor-dependent
timing. Copy protection is notorious for not working with a
accelerated Amiga. These mereley means they aren't well written.
<mike
--
But I'll survive, no you won't catch me, Mike Meyer
I'll resist the urge that is tempting me, mwm@pa.dec.com
I'll avert my eyes, keep you off my knee, decwrl!mwm
But it feels so good when you talk to me.