RAM & performance ...

RAM & performance ...

Post by Ferdinand Goldma » Sun, 05 Nov 1995 04:00:00



Hi all.

I just got an additional 16MB SIMM for my machine, 70ns, no parity.

The problem: When I put it in, performance drops to about 30% of the normal
performance.

Configuration: Some noname board (at least I coult not see any manufacturer
in the handbook), 256K Cache, AMD486/80 CPU, frying at 100Mhz.
There is already one bank 4x1MB 30pin SIMM's and one bank with 8MB 72pin
SIMM used.

The interesting thing is that when I only put in the 16MB SIMM, performance is
ok. When I add either the 4x1MB or the 8MB module, performance drops. I have
tried every possible combination I guess, but I cant get the 16MB module work
with the rest of the memory.

I was wondering if there could be a problem since this is a 'mixed' SIMM
board. I once heard that there could be troubles with that. Could there be
a problem with the board, that if I go over 16MB, performance drops?

Any ideas welcome... I am suffering 8((

regards,
/ferdl
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RAM & performance ...

Post by Jacek Stepniewsk » Mon, 06 Nov 1995 04:00:00


Increase cacheable RAM area.

 
 
 

RAM & performance ...

Post by Joerg Mert » Mon, 06 Nov 1995 04:00:00



: Hi all.
:
: I just got an additional 16MB SIMM for my machine, 70ns, no parity.
:
: The problem: When I put it in, performance drops to about 30% of the normal
: performance.
:
: Configuration: Some noname board (at least I coult not see any manufacturer
: in the handbook), 256K Cache, AMD486/80 CPU, frying at 100Mhz.
: There is already one bank 4x1MB 30pin SIMM's and one bank with 8MB 72pin
: SIMM used.
:
: The interesting thing is that when I only put in the 16MB SIMM, performance is
: ok. When I add either the 4x1MB or the 8MB module, performance drops. I have
: tried every possible combination I guess, but I cant get the 16MB module work
: with the rest of the memory.
:
: I was wondering if there could be a problem since this is a 'mixed' SIMM
: board. I once heard that there could be troubles with that. Could there be
: a problem with the board, that if I go over 16MB, performance drops?
Yep. Known Problem.
Get into your mainboard-CMOS-Setup and enable caching for more than 16
MB of ram. If your Mainboard can't cache more, then you have an old
one.

Also, some Mainboards have problems with dealing PS/2 and Standard
simms in mixed configurations :(

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RAM & performance ...

Post by Ryurick M. Hrist » Wed, 08 Nov 1995 04:00:00


: Hi all.

: I just got an additional 16MB SIMM for my machine, 70ns, no parity.

: The problem: When I put it in, performance drops to about 30% of the normal
: performance.

: Configuration: Some noname board (at least I coult not see any manufacturer
: in the handbook), 256K Cache, AMD486/80 CPU, frying at 100Mhz.
: There is already one bank 4x1MB 30pin SIMM's and one bank with 8MB 72pin
: SIMM used.

: The interesting thing is that when I only put in the 16MB SIMM, performance is
: ok. When I add either the 4x1MB or the 8MB module, performance drops. I have
: tried every possible combination I guess, but I cant get the 16MB module work
: with the rest of the memory.

: I was wondering if there could be a problem since this is a 'mixed' SIMM
: board. I once heard that there could be troubles with that. Could there be
: a problem with the board, that if I go over 16MB, performance drops?

I think it was a discussion quite some time ago about the amount of main
memory versus cache.

The conclusion was generally accepted that if you have too much
main RAM memory and too little cache the performance suffers.

I don't remember exactly but it was some 16 kb cache for each 1 Mb RAM.
(discussed in c.o.l.s, I think)

So, this may be the problem.

Cheers,

--
______________________________________________________________________
Ryurick M. Hristev            ()..()/^\/^\

______________________________________________________________________

 
 
 

1. More ram=less performance (maximum cacheable RAM)

Er, are you sure about this? The problem isn't the size of your cache,
it's the size of your TAG RAM. That's a different beast.

                                Regards,

                                        Richard....


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