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Dram Memory

gerrydoire

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Aug 25, 2008
Messages
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I managed to get a pile of these memory chips:

FUJITSU MB8264-20 64k MEMORIES DRAM

So far none have worked on a AST Six Pack or Directly on a 5150 Motherboard, either
the chips are bad, or ........

Anyone had experiences with these types of chips?
 
The memory soldered to the 5150 is 200 nsec, so it could be defective chips :0
 
Otherwise, dunno--I've used the MB8264A chips with good results. Maybe someone groomed a cat with yours--or there's something in the 8264 (not "A") chip timing that the 5150 doesn't like.
 
Otherwise, dunno--I've used the MB8264A chips with good results. Maybe someone groomed a cat with yours--or there's something in the 8264 (not "A") chip timing that the 5150 doesn't like.

I've tried alot of chips, many different speeds, different makes you name it, never had so many chips gag on me like these MB8264A suckers.
 
The MB8264-20 is listed in the AST document [here].

I tried the memory on the motherboard of a IBM 5150, the computer will boot, no errors or anything overall nothing out of the ordinary, but when you start to run programs,
they would load, run, then suddenly hang and lockup.
 
Looking to buy the following in quantity of 25:

TMS4164-20NL
 
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I got some KM4164B-15 (samsung) from BigDaddysElectronics (they specialize in pinball parts), they only want like $0.75USD each for 4164/4264 DRAMS, I don't know what kind of selection they have, I received the above mentioned Samsung parts, which worked perfect for me, but maybe if you emailed they could take requests if they have them in stock. These guys had the lowest, non-bulk, price I could find on the net for these, short of buying a few hundred pieces.

Hows that AST Sixpak working for you? I recognized your name from here when you purchased it ;-)
 
500 Pieces is overkill, but a group of people buying them and splitting them up, worth the effort?
 
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I got some KM4164B-15 (samsung) from BigDaddysElectronics (they specialize in pinball parts), they only want like $0.75USD each for 4164/4264 DRAMS, I don't know what kind of selection they have, I received the above mentioned Samsung parts, which worked perfect for me, but maybe if you emailed they could take requests if they have them in stock. These guys had the lowest, non-bulk, price I could find on the net for these, short of buying a few hundred pieces.

Hows that AST Sixpak working for you? I recognized your name from here when you purchased it ;-)

Can never have too many 8-bit cards for my large collection of obsolete computers :p

I was looking at one of my IBM 5150's and noticed the memory soldered to the motherboard was TMS4164-20NL,
so bringing my insanity to the next level for collecting these computers in the first place, I figured why not get
the exact same memory for the empty slots to make it all uniformed, has anyone else done this?

Are we all this crazy for wanting to do this, when does the madness end lol ;)
 
Can never have too many 8-bit cards for my large collection of obsolete computers :p

I was looking at one of my IBM 5150's and noticed the memory soldered to the motherboard was TMS4164-20NL,
so bringing my insanity to the next level for collecting these computers in the first place, I figured why not get
the exact same memory for the empty slots to make it all uniformed, has anyone else done this?


I have never gone as far as trying to match EXACT chips, its way too hard these days considering most these chips have been out of production for 20+ years, I have a pretty much "take whatever is compatible and obtainable" approach ;-)

Are we all this crazy for wanting to do this, when does the madness end lol ;)

Most likely, I don't think it does, I am like 10-15 years in, no real signs of a cure ;-)
 
No matter how many articles I googled, I still don't understand the relation between DRAM and expandable RAM to Conventional RAM.

Do modern computers of today still use DRAM for conventional memory? And why isn't it possible to setup the computer to use expandable RAM (like SIMM's) as expanded conventional memory? Does it has something to do with timing?
 
It's all DRAM. DIMMS, and SIMMs are not expanded memory, they're just a different way of putting memory in a computer. It's a lot easier to slide in a little card and go click - than to install a bunch of tiny chips.

Terms like expanded, extended, upper, high, etc are just how the computer is using that memory.
 
No matter how many articles I googled, I still don't understand the relation between DRAM and expandable RAM to Conventional RAM.

Do modern computers of today still use DRAM for conventional memory? And why isn't it possible to setup the computer to use expandable RAM (like SIMM's) as expanded conventional memory? Does it has something to do with timing?

Yes, modern day PCs still use DRAM (DDR SDRAM)

Some early computers or computers with special requirements computers used SRAM, but most everything for like the past 25 years is DRAM, except for your CPU cache, cache memory is usually SRAM.
 
...And why isn't it possible to setup the computer to use expandable RAM (like SIMM's) as expanded conventional memory? Does it has something to do with timing?
Forgot to address your conventional vs expanded concern

That has to do with the way the PC was designed around an 8088, and how it could only address 1MB of RAM, and subsequent PCs (even when equipped with 286 CPUs which could address 16mb) holding to that addressing for compatibility. I would read into the 8088/8086 architecture if you want to learn more about this topic, its not a topic of RAM/DRAM, but of CPU limitations and system designs. Conventional RAM is just the base 0-640K chunk, expanded is the RAM past that (though BIOS and other ROMS usually live in 641-1MB region, expanded usually sits over the 1mb region).

Some NON-PC computers never had these limitations placed on DRAM, and some had even stricter limitations on DRAM, it was all about the architecture and design decisions.
 
It turns out my memory chips were not at fault, The AST Memory card was at fault, but all fixed now :)
 
Yes, modern day PCs still use DRAM (DDR SDRAM)

Some early computers or computers with special requirements computers used SRAM, but most everything for like the past 25 years is DRAM, except for your CPU cache, cache memory is usually SRAM.

Sorry for being a bit off topic.

Ah ic. I have a 80286 board with a total of 1MB DRAM on bank 0 and bank 1.
There's an additional smaller chip next to each pair of DRAM chips, the socalled parity chips?

Each bank has seems to have 4 DRAM chips which is 128k each. Is it possible for me to replace them with 512kx4 DRAM chips? (tptal would be 2M).

Or... is it a better to expand beyond 1m with the use of the DIPP banks next to it?
 
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