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From: rashid@magnus.ircc.ohio-state.edu (Robert G Rashid)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Why SRAMS in Mac Laptops?
Keywords: Macintosh, SRAMS, Question
Message-ID: <1991Mar2.200511.25897@magnus.ircc.ohio-state.edu>
Date: 2 Mar 91 20:05:11 GMT
References: <1991Mar1.020935.7107@dartvax.dartmouth.edu>
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In article <1991Mar1.020935.7107@dartvax.dartmouth.edu> watt@eleazar.dartmouth.edu (Gill Watt) writes:
>
>howdy,
>
>I have a curiosity question:
>
>Why do the mac laptops use SRAMS instead of the standard
>DRAMS?
>
>Is it because DRAM refresh circuitry consumes a lot more
>power?  If so, how much more?
>
>Anyone know any other reasons?
>
>Thanks.
>
>
>-- 
>---------------------------------------------------------------------
>Gill Watt (watt@eleazar.dartmouth.edu)
>Thayer School of Engineering, Dartmouth College, Hanover, NH  03755
>---------------------------------------------------------------------


There is a company that makes a memory board for the portable which uses drams
as the memory chip.  The board takes care of memory refresh, as I understand,
and the total power consumption is less than the equivalent sram or static
ram chip.  The drawback is in sleep mode, where the chips require power to
maintain memory.  This is not the case with sram and static ram chips.

I just got the board from Computer Care, and am happy with it.  They have
4M chips on the board, but it was cheaper than 4M (or 3M) of static ram,etc.
Since I am usually near power a few times a day, I can charge if nec. and still
use without power for a few hours.  I notice that there is more power used 
now that I have 4M than when I had 1M (no suprise).  

Disclaimer: I have no connections with Computer Care, except as a satisfied
customer.
-- 
  | Bob Rashid                |   Rashid.1@osu.edu |
  | College of Dentistry      |   305 W. 12th Ave. |
  | The Ohio State University | Columbus, OH 43210 |