#32 & 16-bit RAM
20 messages in this thread
If I were to buy an 030 card with i meg of 32-bit RAM for an A2000 yet
keep 8 meg of 16-bit RAM would; A)the set up work okay and B)would it
SERIOUSLY slow down the speed of the machine? Thanks for any help or
advice!
Sure it'd work, except that you'd loose a meg or two of RAM somewhere —
Zorro-II only lets you address 8 megs. And if you mean "would it be
SERIOUSLY slower than with 8 megs of 32-bit RAM?" the answer is yes, it
would be SERIOUSLY slower.
Depending on how many and what kind of apps you are running, and which 030
card you planning to buy (the A2630, for example, only expands easily to 4
megs of 32-bit RAM), it might be a good cost/performance trade off to do 4
megs of each. (you can remove or disable 4 megs on your Zorro-II card, but
I don't think you'd _have_ to — Autoconfig will do it when it realizes
there ain't enough address space). You'll get a lot slower when your
machine is heavily loaded, but for most interactive use you should be
doing fine. I don't do any fancy-pants graphical rendering stuff, so I
usually get along wonderfully with 4 megs of fast RAM in most of my
machines.
Dale Larson
– An Amiga Software Engineer with lots of time on his hands.
There are also a number of processor cards that don't AutoConfig memory if you
don't want them to. As an example, I have a PPI 040 board with 8MB and a GVP
SCSI card with 4MB. Currently the PPI autoconfigs 2MB in Fast RAM space and the
GVP autoconfigs 4MB there for 6MB total. When the machine boots, a PPI utility
program adds the other 6MB of RAM on the 040 board into the memory pool at an
address above the 8MB Fast RAM barrier (above the ROM in fact — into the realm
of 32-bit address space).
I *could* have the PPI board autoconfigure *NO* memory and then put
8MB on the GVP card. That would give me 8MB of Fast RAM and 8MB of
040 (32-bit) RAM. That, according to the PPI manual would cause
things to slow down though since the 040 would have to go through the
bus to access any configured RAM until the 32-bit 040 RAM is added to
the RAM list. By that time, all the device drivers and filesystem
code will be using the 16-bit GVP RAM space since it will be the only
Fast RAM available. This, once again, will cause a slowdown since the
040 will have to access 16-bit RAM to do any filesystem stuff from
that point on. Yuck.
So, it's a good idea to make sure that some of your 32-bit RAM can be
autoconfigured for the purpose of putting boot-time code into it.
32-bit RAM is almost always configured with a higher allocation
priority than 16-bit RAM so that it gets used first.
Okay, to be specific; I purchased a GVP 030 (40 mhz) card with 4 meg of
32-bit RAM. If I keep my fully populated 8-up! 8 meg (16-bit) RAM card
plugged in will the 16-bit RAM start filling up if I go over the 4 meg of
32-bit RAM? Thanks. (BTW, I'm extremely sorry about your job. Best of
luck.)
You can tell a GVP 030 (or 040) card to have the on-board RAM be "extended"
i.e., outside the usual auto-config address space. This will enable you to
keep your 8MB 16 bit card and put up to 16MB on the GVP card.
Hope this helps,
Paul.
Paul,
I have one of your 030 combo boards with 9 megs of 32 bit ram and 4
megs od 16 bit (1 meg chip). All of my 32 bit ram is configuired outside
of the autoconfig space. Is there any advantage to having any of it
autoconfig?
…Steve
====>>> Motorola 68030 Inside <<<====
Hi Steve. The only advantage of having some 32 bit RAM in the autoconfig range
is if you have another Zorro II card that does DMA. Then it can DMA into the
faster 32 bit memory. If you don't have one of those, then you're fine the way
you've got it now.
Paul.
BUT all DMA has to go thru the 16 bit bus (a2000) anyway so what good does
it do unless you have your DMA on a 32bit bus (a3000/a4000)??
Sean.
You're right. I'm just saying we gave users the option of putting memory in or
out of the auto config space so that they'd have memory for Zorro II cards to
DMA into. In your case it's not a problem because you have "other" (16 bit)
memory in the autoconfig space, but for people without that, if they put all 32
bit memory out of the autoconfig space then a Zorro II card with DMA
capabilities could only DMA into SLOW chip RAM.
Of course, on a GVP Combo card it can DMA into its own 32 bit memory without
ever going through the Zorro bus, which is definitely a big performance win.
I have a 25 MHz GVP Combo II accelerator (68EC030) that I would like to
upgrade. Can I just install a 33 MHz or 50 MHz 68030 w/MMU and a new
clock, or are other mods required?
Unfortanately, you cannot just change the processor and clock crystal, because
the PALs would need to be upgraded also. You should call GVP regarding upgrade
paths however, because we like to be as flexible as possible and may be able to
work something out for you.
Regards,
Paul.
I have a 25 MHz GVP Combo II accelerator (68EC030) that I would like to
upgrade. Can I just install a 33 MHz or 50 MHz 68030 w/MMU and a new
clock, or are other mods required?
I appreciate the concern, but appologies aren't in order. When we have
parties at Commodore for people going away, we're pretty sure those who
are staying have it worse off than those who are going away 🙂
Dale Larson
– An Amiga Software Engineer with some time on his hands.
Les,
yes, you can use 32 and 16bit memory at the same time – supposing the
32bit memory has a higher priority than the 16bit FastMem, programs
looking for Fast or Public Memory will first use up the 32bit RAM, if
nothing's left they will go for the 16bit FastMem.
// Chris coming in from Germany
\X/ on AutoPilot 1.051……….
I presume that the card wouldn't put it's ram into the fast ram area as
this would be stupid as it limits ANY such card to 8MB. I have a Fusion
Forty which can use up to 32MB of 32bit ram. I also know that all the C=
turbo boards can be updated to use up to 128Megs of ram. My '040
configures its ram at an address outside that of the 16bit range of the
68000 so that it can only be accessed by the turbo board and cannot be
used when this is off (which is only once a month or so). It may be true
that the mashine slows down when it has to access 16bit memory… BUT it
only slows down to a speed which lies ABOVE that of any 68000 amiga as the
'040 and '030 are faster than the 68000 in the time they need to execute
commands.
Leslie,
A) will be okay if your 030 board does _not_ autoconfig its 32bit RAM as
the Amiga's AutoConfig Menory size is restricted to 8 Megs FastRAM. Some
boards let you choose – via jumper setting or software controlled (EEPROM)
– how much of their 32bit memory to autoconfig. CSA's MMR for example
doesn't have this option – it just adds the 32bit memory via an istall
program which means anything run/loaded before that (for example, hdisk
drivers) will run in 16bit memory.
B) Everything running in 16bit memory when running on the 030 board slows
things down considerably as the processor has to spend many cycles waiting
for the 16bit RAM on the 7MHz bus.
If your board _can_ autoconfig its 32bit memory I would certainly let it
do so and configure the 16bit RAM board for 6 (if poss) or 4 Megs and –
finances allowing – have as much 32bit RAM as the board/money allows!
If you have more 32bit RAM you could also load the KickStart into 32bit
RAM ('FaastROM') thus speeding up many system functions, most notably
screen output – your windows will just pop onto the screen…
// Chris coming in from Germany
\X/ on AutoPilot 1.051……….
Thanks very much for the information! I'm keeping your message and will
apply what you said when the board I ordered arrives. If I have any
questions I'll post another message.
Leslie,
The 32 bit ram is much faster than the 16 bit ram which is on
you're 8MB 16bit ram card. I presume that what will happen is that your
system will decide that the 32bit ram will be used first, than the 16bit
ram, and then the 16bit chip memory. All that this means is that all
programms which get memory first will get 32bit memory and that as soon as
this is gone the system will delve into its reserves of slower 16bit ram.
The system should keep on ticking as it did before (just a bit faster).
The second question which you put is very easy to answer. YES. Using an
amiga 2000 with a turbo board slows down the turbo board a little :-). If
you want you can say that the amiga gains a great deal of speed and the
turbo board looses a little due to the 16bit interface which acts as a
bottle neck but is part of the game as the turbo board doesn't really work
without the amiga.
I hope that that helps you a little and doesn't confuse you.
Sean.
Thanks, Sean. That information was just what I was looking for!