erk@americ.UUCP (Erick Parsons) (04/03/91)
Well it's tax time and this year I just happened to make out like a bandit
soo... I am in the process of wading through tons and tons of information
on Accelarators for my A500 to sink megabucks, again, into my favorite computer.
I have come to these conclusions (be they right or wrong)
o In order to fully utilize the potential of a 68030 accelarator
In this case the Mega Midget Racer by CSA, one needs at least
256K of 32 Bit Static ram on board to realize any significant
bang for the buck, with 512K being optimum as that's max for
onboard ram without the addition of a daughter board.
o 32 bit microprocessors are kludgy on 16 bit busses like that
of the A500.
? What is in fact the minimum amount of 32 bit wide ram necessary
to make the 68030 a blazingly fast, efficient accelarator ?
Is static ram preferable to Dynamic Ram ?
? Is my 16 bit ram going to slow things down? I have a sizable
investment in ram to date (5 megs)
? Do these accelarators use the same simm memory expansion modules
that other expansion boards use ? i.e. 1M x 8, and is the fact that
it is 80ns access time a detriment to burst mode caching ?
? Will I realize any significant increases in speed in general with
Caching disabled on a 33 MHZ '030' / 68882 / 512K 32Bit Static Ram ?
? " Caching enabled ?
o A math co-processor will speedup dramatically CAD, 3D-rendering
programs and Spreadsheets that are floating point intensive.
? Will the addition of a 68882 co-pro. do anything for such things
as flight simulators and or simulations.
o There seem to be two versions (if not more) of '030's floating
around these days. There is the MMU and non MMU.
? Would it be worth it at some later date to have gotten the MMU
'030' ? i.e. Unix implementations running rampant in the forseeable
future.
Opinions Wanted
o There are a thousand things that I would like to get for my Amiga
but only so much money. Would I be better off buying an AdSpeed
accelarator for a little over 200.00 and increasing data storage ?
-or-
o Should I go with a 33 MHZ MMU w/ 68882 co-processor and 512K of
Static Ram as a package for well over a thousand dollars and
forget about buying anything else for expansion till next April ?
"I feel the need for Speeeeeeed "
All replies cheerfully refunded if you are not 100 % Happy :)
--
Erick Parsons, Sacramento erick@sactoh0.sac.ca.us <-- Right off the freeway --
{ames att sun }!pacbell!sactoh0!pacengr!americ!erk <-- At the end of the road --davem@hp-lsd.COS.HP.COM (Dave K. Martin) (04/06/91)
Well, I can't answer all of your questions but I can give an opinion or two :-) :-) I currently have a 25 mhz Mega Midgit Racer with 0k static and 0m dram installed. It does make a difference in some operations on my A-2000. If I'm working out of ram (7 meg of 16 bit ram), unarcs, GIF conversions, and such operations run between 1.5 and 2.5 times faster. Most of the applications that I use, ProWrite, Photon Paint, etc don't seem to be noticiably faster. Also anything that involves disk access won't change very much. From what I've read, adding the dram will make more of a speed difference than the sram will. Adding both will give the best results. The following comes from the MMR User's manual: The CSA Mega-Memory (tm) DRAM daughter-board is available in two different versions: one that has sockets for DIP memory chips and fits in the A1000 and A500, and one that has ZIP memory chips soldered directly into the board and fits in the A200000 as well as the A1000 and A500. The A1000/A500 board will work in an A2000 but hangs out past the side of the system precluding reinstalling the cover. Soon, I hope to be able to report on how much effect 2 meg of 32 bit ram has. Then I can try the cache and burst options also. Hope this has answered at least one question. (Give up my MMR? Absolutely not! ....Well, maybe for an '040 board. ;-) davem test som
daveh@cbmvax.commodore.com (Dave Haynie) (04/09/91)
In article <erk.1724@americ.UUCP> erk@americ.UUCP (Erick Parsons) writes: > o In order to fully utilize the potential of a 68030 accelarator... > one needs at least 256K of 32 Bit Static ram on board Probably much more memory than that. With 256K of RAM, you might get a bit of extra performance by putting the KickStart code into it. Bit in general, if you don't have 32 bit RAM for programs to run in, you're not going to get much speedup, except in programs specifically coded for a 68882 FPU. > o 32 bit microprocessors are kludgy on 16 bit busses like that > of the A500. Well, "less than optimal" is a better way of looking at it. All Motorola 32 bit CPUs are optimized for 32 bit buses, and actually run a little worse than the 16 bit CPUs on 16 bit buses. In both the 68020 and 68030, for example, the CPU prefetches 32 bits of instruction memory at a time. This is no loss and often a win on a 32 bit bus, but can be a loss on a 16 bit bus, since a 32 bit read always takes two memory cycles, and there's no guarantee the second word will actually be used. On-chip caches can more than make up for these inefficiencies, but out of 16 bit RAM, you can't get much beyond a 20% or so speedup in typical 68030 operations (benchmarks show a little more speedup) with both caches on. > ? What is in fact the minimum amount of 32 bit wide ram necessary > to make the 68030 a blazingly fast, efficient accelarator ? That depends on how much memory you normally use. If 1MB on an A500 is plenty, you can probably get by with 1MB of 32 bit RAM and see most of the potential acceleration you can get. I'm never happy with less than 4MB, which is for CAD, DTP, and programming use. Folks doing 3-D rendering need as much as they can get. > Is static ram preferable to Dynamic Ram ? In an ideal world, yes. Problem is, static takes up more room than dynamic and it's much more expensive. You're much better off with a meg or two of DRAM than 256K-512K of SRAM. > ? Is my 16 bit ram going to slow things down? I have a sizable > investment in ram to date (5 megs) Slow down relative to what? A 32 bit CPU will be running slower from 16 bit RAM than it would 32 bit RAM. However, if you're out of 32 bit RAM, it's better to have that 16 bit RAM available than nothing at all. Any good accelerator setup will organize system memory lists so that the 32 bit RAM is used before the 16 bit RAM. > ? Do these accelarators use the same simm memory expansion modules > that other expansion boards use ? i.e. 1M x 8, and is the fact that > it is 80ns access time a detriment to burst mode caching ? Some use SIMM, others don't. Some support burst, others don't. Systems that support burst generally require 4MB chunks of 32 bit RAM, non-burst systems may allow 1MB or 2MB upgrade increments. The A3000 actually supports 1MB upgrades and burst, up to 4MB, or 4MB upgrades and burst, up to 16MB. But it uses custom logic not generally available on accelerator add-ins. > ? Will I realize any significant increases in speed in general with > Caching disabled on a 33 MHZ '030' / 68882 / 512K 32Bit Static Ram ? > ? " Caching enabled ? You don't want caching disabled with that little bit of Fast RAM. Make sure that the 68030 hardware allows caching of non-Chip 16 bit Fast RAM, or you'll not see much speedup in that system. > o A math co-processor will speedup dramatically CAD, 3D-rendering > programs and Spreadsheets that are floating point intensive. To some extent. Anything that uses the ieee math libraries will get an automatic speedup with an FPU present. Real floating point intensive programs, like renderers and the occasional CAD program, will come in versions with FPU code in-line, rather than via function calls, which can speed things up 25x or more, depending on the floating point component of the problem. > ? Will the addition of a 68882 co-pro. do anything for such things > as flight simulators and or simulations. Most games don't use floating point, but rather fast fixed point, if integers won't do. Any games that do use floating point probably use the Motorola FFP libraries, which don't get any FPU acceleration. However, since the FFP routines are in ROM, you can speed them up 2x-4x with by putting the ROM code into 32 bit RAM (via SetCPU or one of these CSA-type hardware hacks). > o There seem to be two versions (if not more) of '030's floating > around these days. There is the MMU and non MMU. Nope, there's only one 68030, it has an MMU. The only 68020 board out for Amigas with an MMU, to my knowledge, is the C= A2620. >Erick Parsons, Sacramento erick@sactoh0.sac.ca.us <-- Right off the freeway -- -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "That's me in the corner, that's me in the spotlight" -R.E.M.
mascot@bnr.ca (Scott Mason) (04/11/91)
In article daveh@cbmvax.commodore.com (Dave Haynie) writes: >In article erk@americ.UUCP (Erick Parsons) writes: > >> Is static ram preferable to Dynamic Ram ? > >In an ideal world, yes. Problem is, static takes up more room than dynamic >and it's much more expensive. You're much better off with a meg or two of >DRAM than 256K-512K of SRAM. > There's probably some confusion about different memory uses in the larger article Erick writes that Dave has not addressed here. Static RAM is rarely used as the main memory. It is most commonly used in external caches. Static RAM: fast, does not require a memory controller Dynamic RAM: denser (fewer chips for same memory size), more power efficient, less expensive Because of the cost, density, and power requirements of SRAM, it is used only in performance sensitive applications where its high speed is an absolute requirement and where total memory size is relatively modest. Examples include the memory of Digital Signal Processors and the cache memories of high performance general purpose computers. Because of the favourable cost/bit ratio DRAM is generally used for larger memory arrays. The cost and complexity of a DRAM memory controller becomes less significant compared to the total memory cost. Scott.