Quote:>I'm about to upgrade my 486/dx2 66 from ISA to PCI bus motherboard. I
>have heard that boards that use 36 pin ram will slow performance since
>they use a 32 bit memory controller instead of 64 bit. However I
>suspect this is pointless and that I might save the cost of trading in
>my SIMS with no penalty since I will only be running a 486 on thsi
>board becasue the 486 would not be able to make use of a 64 bit data
>path anyway.
>Any thoughts, comments or suggestions?
This is POPPYCOCK! The 36 pin SIMMS are NOT 32bit! That should be OBVIOUS
to ANYONE that knows about such things! 32 PINS data + 2pins for power leaves
only 2 pins for address(and that isn't even including the cas/ras, etc...)!
In other words, it is only good for 4BYTE memory!
The 36PIN SIMMS are 8 or 9(w/parity) bit memory, and are merely a packaging
device! A 386sx
will typically require 2 banks(or 16 bits), and a 386DX or higher typically
requires 4(for 32 bits). How it accesses the memory is the MBs job.
Go with what is the best for you. The larger chips allow more memory in less
space. The smaller ones allow a better distribution, and a better upgrade
path for the moment.
Hopefully, they STILL have the 4 or 8 way memory interleave. Doing that with
8 SIMMS can allow you to APPROACH 8ns memory! 60ns memory accessed sequentially
on a 8 way interleave will actually be 7.5ns! Of course, any deviation from
truly sequential access will degrade performance by neccesitating wait states.
Steve
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