[comp.sys.cbm] DRAM Speed question

XWUU@PURCCVM.BITNET (02/09/91)

I have the opportunity to buy some DRAM chips at a blow away price!
These are 256 X 1 120ns DRAM chips.
My Ram Expansion Unit uses 256 X1 150ns chips.  I recently upgraded my
REU 1764 to 512K and want to push it up to 1 or 2 Meg.  Can I use these
120 nanosecond chips with the 150's that are already in there?

If not - what will`the problem be; what does the problem "look like" to
the computer.  If I can use them, what should I watch for; what potential
problems exist with the mis-match?

Thanks in advance for the the aid and info!
Kirk A. Janowiak
XWUU@PURCCVM

cinf07@vlsi.polymtl.ca (Miguel Pedro et Louis Sabbat) (02/12/91)

In article <91039.165224XWUU@PURCCVM.BITNET> XWUU@PURCCVM.BITNET writes:
>My Ram Expansion Unit uses 256 X1 150ns chips.  I recently upgraded my
>REU 1764 to 512K and want to push it up to 1 or 2 Meg.  Can I use these
>120 nanosecond chips with the 150's that are already in there?


Yes.
150 ns refers to the fact that an access to memory will require a maximum of
150 ns. If you use memory chips with an access time of 120 ns, the data
will be available faster. Of course, your CPU won't run any faster.

The only requirement is to use the same DRAM type that's already in the REU.
(i.e. 256 X1)


--


   Miguel Pedro
   (if18@info.polymtl.ca was my old account)