Mixing Ram Types 286 \ VOGONS

Mixing Ram Types 286

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First post, by devon

Posted on 2019-10-03, 02:47

devon Offline

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Was wondering if it is okay to mix NMOS and CMOS ram? I have a 286-12 that kept getting memory parity errors, ran check it and it found bad ram in bank 0.
I put in some NEC D41256 ram that is NMOS mixed with the existing Hyundai chips and the NEC ram runs 20c hotter. however no more memory errors and check ran multiple passes with no problems.

Anyways just would like some thoughts on mixing the 2 types and hope that it wont bring me any long term problems.

Reply 1 of 3, by Horun

Posted on 2019-10-03, 03:01

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NMOS draws more power and does not dissapate heat as easily as CMOS and is why CMOS is basically the standard. Mixing two diff design types of ram like you did can be OK if it works and is differant than mixing something like EDO with FPM. Am sure someone else can elaborate more on this but until then you might read this:
https://www.elprocus.com/difference-between-n … mos-technology/

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 2 of 3, by derSammler

Posted on 2019-10-03, 07:35

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The system won't see whether a RAM chip is CMOS or NMOS, so yes, you can mix them. But NMOS should really be avoided these days, even in vintage hardware.

Reply 3 of 3, by maxtherabbit

Posted on 2019-10-03, 14:05

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derSammler wrote:
NMOS should really be avoided these days, even in vintage hardware.

why? I could really not care less about power consumption in hobby PCs and overheating is usually not a big problem on pre-486 stuff either

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