S) 5.0 Adding System and Cache Memory
Q) 5.1 How do I add memory to my PS/2 off the motherboard?
[Test from PC Magazine January 28, 1992]
There are several RAM cards out there for the PS/2 and you do not necessarily
need a 32bit card to get the max performance as will be shown.
(all cards tested on a Model 70-A21).
KEY:
%READ = The read speed of memory using 4K blocks in sequence from 0MB to 16MB
in relation to motherboard memory writes.
%WRITE = The write speed of memory using 4K blocks in sequence from 1MB to
16MB blocks in relation to motherboard memory writes. (not less than
1MB due to that memory being of the resident OS)
TESTED = The as TESTED config, 8MB of 80ns RAM was used for each card.
MAX = The maxium memory able to be put on the RAM card in MB. Though MCA
computers don't allow DMA or direct memory access transfers past
16MB, certain OS's for non-DMA type usage ie disk caches and EMS.
SIMM = 9 bit or 36 bit SIMM requirements.
SOCKET = The amount of SIMM sockets on the RAM card.
256-16 = The size of SIMM it can take in K or MB.
INTEGR = The integration of the card to the system. BIOS is the right way
and allows all memory to be read at or during POST. T0 is Track 0
method which is not as per IBM spec. This uses a special driver from
the hard drive before the OS loads and thus is not usually cached and
is reflected below in slower speeds. BOTH of course means both can
be used (on the CuRAM if BIOS is used 16MB is max and if T0 is used
then 32MB is possible). T0 also has the problem of not being tested
by the system. Unless the card does this any memory errors do not
get mapped out.
POST = Whether or not the memory is shown on the screen at POST. All BIOS
type card 'POST' their memory, but some do not show it.
BKFILL = Whether the RAM card allows backfill of any deficiencies of the 640k
base system RAM, more useful in 1MB systems and can allow 0
wait access through the MCA channel and increase performance on
such systems by 50%.
PORTS = Either (P)arallel or (S)erial included or as an (o)ption. PS means
one parallel and one serial included, PPSo means there is an option
for 2 parallel and 1 serial port and so on. NONE means no ports are
provided or offered as an option.
MODELS = The supported models, A = Models 50-65SX, B = Models 70-80 and C =
Models 90-95. Note if BC is specified it means a 32bit card. Cards
with only a B designation do not work with 50-65SX or for some
reason the Model 90-95 even though it was a 32bit card.
____________________________________________________________
| | % | T | | | S | | | | | | | I | | B| |M
| % | W | E | | | O | | | | | | | N | | K| P |O
| R | R | S | | S | C | 2| | | | | | T | P| F| O |D
| E | I | T | M | I | K | 5| | | | | | E | O| I| R |E
| A | T | E | A | M | E | 6| 1| 2| 4| 8|16| G | S| L| T |L
| D | E | D | X | M | T | K| M| M| M| M| M| R | T| L| S |S
-----------------------------------------------------------------------------
AboveBoard MC |80 |71 | 4 | 32|9 | 8 | Y| Y| N| Y| N| N|BIOS| N| Y|PSo |AB
-----------------------------------------------------------------------------
AMS Memory |66 |46 | 8 | 16|36 | 4 | N| Y| Y| Y| N| N|BIOS| Y| N|PSo |BC
32DI | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
Capital OS/RAM |80 |71 | 8 | 8|9 | 8 | Y| Y| N| N| N| N|BIOS| N| N|NONE|ABC
32 | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
Capital OS/RAM |80 |71 | 8 |128|9 | 8 | N| Y| N| Y| N| Y|BIOS| N| Y|NONE|ABC
32+ | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
CuRAM MC32 |80 |50 | 8 | 32|36 | 4 | N| Y| Y| Y| Y| N|BOTH| Y| N|NONE|BC
-----------------------------------------------------------------------------
Kingston |80 |71 | 8 | 16|36 | 4 | N| Y| Y| Y| N| N|BIOS| Y| N|NONE|BC
KTM 3011-4 | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
MicroRAM |80 |71 | 8 | 32|36 | 4 | N| Y| Y| Y| Y| N|BIOS| Y| Y|NONE|ABC
SC | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
MicroRAM |80 |71 | 8 | 32|9 | 8 | Y| Y| N| Y| N| N|BIOS| Y| Y|PSSo|BC
386 | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
Parity+Plus |69 |50 | 8 | 8|9 | 8 | Y| Y| N| N| N| N| T0 | N| N|NONE|B
P32010 | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
RAMQuest |80 |45 | 8 | 8|9 | 8 | Y| Y| N| N| N| N|BIOS| Y| Y|PS |AB
16/32 | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
SIMMply-RAM |80 |71 | 8 | 32|36 | 4 | N| Y| Y| Y| Y| N|BIOS| Y| N|NONE|BC
for PS/2 32bit | | | | | | | | | | | | | | | | |
-----------------------------------------------------------------------------
The winner here was the MicroRAM SC (a 16 bit card). Both cheap and with many
memory options. The 386 version offers a parallel and dual serial option that
would be a wise purchase if you needed those but the 9bit memory it uses needs
to be installed in banks of four and thus in general the SC is the preferred
solution offering 100% of the performance of its 32bit brother in a 16bit
config. (note: I don't know if the 16bit cards will work as well with
processor upgrades, but clearly they worked as well in the 386/25MHz system
and were recommended for the 486 90/95.)
Please note that the 16bit cards scored just as well in most cases and are
less money. Any card the scored percents of 80/71 operated at 0 wait states.
The MicroRAM allows 1 wait state with 120ns and matched memory with 100ns,
it will operate at 0 wait states with 85ns memory (this was not tested in
this test and is purely from the manufacturers mouth).
Q) 5.2 How do I add cache memory to my PS/2?
Q) 5.3 Can I use 4MB modules if IBM only calls for 2MB?
Supposedly you can, but not per IBM. I had both a 80/20MHz and 80/25MHz here
recently with both 4MB and 2MB modules, but forgot to test this when I had
the chance. I don't want to say you definitely can until I or someone I trust
has done so. Until then by the memory at your own risk, it may very well
work, but give data dropout at times.
Q) 5.4 Who has memory the cheapest?
Q) 5.5 Is there a way to identify a PS/2 RAM card or SIMM?
[From Aron Eisenpress <AFECU@CUNYVM.CUNY.EDU>]
If the simm slots are 3 on the left and 1 on the right then it is a 2-14. If
the slots are 2 and 2 then it is a 2-8mb adapter. There was a recall about 4
years ago on 2-14mb adapters that had data integrity problems with 4mb simms,
but the problem was not ever produced outside the lab that was reported. If
it is 2-14 and has a sticker then it is probably one of the problem adapters.
However, the recall has expired and IBM is no longer providing replacements.
Q) 5.6 What is the ECC memory option on some of the newer PS/2s?
Q) 5.7 What cache size do I have/can I upgrade to?
email:Chris Feeny alkemyst@shadow.net---------------\
Return to PS2 FAQ main menu