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From: lam@hyper.hyper.com (Edmund C. Lam)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: SIPPs and SIMMs
Message-ID: <1991Mar8.042318.7060@hyper.hyper.com>
Date: 8 Mar 91 04:23:18 GMT
References: <1991Mar4.164609.3988@rodan.acs.syr.edu> <21688@teda.UUCP>
Reply-To: lam@hyper.UUCP (Edmund C. Lam,,)
Distribution: usa
Organization: HyperCube Inc.
Lines: 22

Most PC motherboards take SIMM or SIPPs.  SIMM and SIPPs are identical
with SIPPS have soldered pins.  This makes motherboards supporting
SIPPS cheaper (i.e., a row of machined socketed pins is cheaper than
a SIMM row socket).

While the majority of memory modules are of the 'x 9' or 'x 8', some
motherboard manufacturers also support 'x 4+4 + parity'.  This modules
come in 256K or 512K blocks.  In the case of the 256K module, 2 256K x 4 plus
1 256K x 1 DIPS are soldered on a PC board which can be mate to a SIMM
socket.  The 512K module uses 4 256K x 4 and 2 256K x 1.

This style of DRAM seems to be popular with the clone motherboards from R.O.C.,
(DTK 2030 and 2530, BioStar MB1325's etc...).   I know that this style of
memory is being phased out.  The new DTK 2530's will only accept 'x 9' 
memory.

N.B. the 'x 4+4 + parity' is my own notation.
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        - Edmund C. Lam (lam@hyper.com)           -
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