NEC 4164-12

dwight dkelvey at
Sun Oct 29 00:14:04 CDT 2017

One caution for 4164s. When they first came out, there were some that were 256 cycle refresh and others that were 128 cycle.

There is no way by looking at them to tell which is which other than getting a matching original manufacture document.

Many machines expect 128 cycle. You can use 256 cycle on chips designed for 128 but not the other way around.

Most Z80 setups only do 128 unless it has additional hardware to handle the extra bit ( not to likely ).


From: cctalk <cctalk-bounces at> on behalf of Ethan Dicks via cctalk <cctalk at>
Sent: Saturday, October 28, 2017 1:31:36 PM
To: e. stiebler; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: NEC 4164-12

Hi, Emanuel,

I have a quantity of 4164 DRAM from the Comboard days, new in tube.  It is
likely to mostly be 150ns and I don't know the brands until I dig it out,
but I will check when I get home.  If it matches what you need, I'm happy
to send some to you.


On Oct 28, 2017 12:32, "emanuel stiebler via cctalk" <cctalk at>

Hi all,
anybody has some spare in the bin, he doesn't need?

Looking for 18 pieces, preferably NEC, -12.


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