[plug] (OT) - Hardware - Motherboard and RAM

[Mike]

At 11:54 PM 16/9/2001 +0800, you wrote:
>The requirement for pairs is a function of the motherboards, not the RAM.
>The Pentium class motherboards and nearly all of them up until they were
>only coming with SD-RAM slots used a memory interleaving system that
>required the banks to be filled in pairs where (literally) memory address
>"0" would be on the first bank and memory address "1" would be on the
>second, "3" is on the first, "4" is on the second, etc...  You could take
>the same 72-pin EDO RAM and stick (one of) it in your old 486 (which didn't
>user interleaving) and it would function quite happily with just a single
>stick.

Its not interleaving. Its the binary width of the data path,

The old 30pin ram was 8 bits wide, you needed 4 for a 486 because
the data path is 32 bits.

(For many 386 machines you only needed 2 because the data path
is 16 bits wide)

The now old 72pin ram, whether edo or fast page mode is 32bits
wide, you need 2 for a pentium because the data path is 64 bits.

What would be real interesting for speed would be a motherboard
and cache that supported parallel access to 1024 or 2048 bits
heck of a lot of sockets but would it be fast - even for the
older FPM or EDO rams !



Kind Regards  ~`:o)

Mike Massen
Network Power Systems
Perth, Western Australia  Ph/Fx +61 8 9444 8961 

Power system in Jungle, Twin tyre car, Differential gauge
http://members.iinet.net.au/~erazmus/index.html

Some say there is no magic but, all things begin with thought then it becomes
academic, then some poor slob works out a practical way to implement all that
theory, this is called Engineering - for most people another form of magic.