CAS Rating of DIMMs

Randall Hofland rhofland at
Sun Feb 20 15:45:59 EST 2000


    What I find interesting and surprising is that ALL the CAS3 DIMMs of the
same manufacture were to some degree capable of faster bus speed than their
CAS2 (in some cases dramatically faster, such as the Mitsubishi brand PC100
DIMMs). If I understand the rating system (and it seems I don't), CAS2
should be faster. Perhaps this is an issue of motherboard settings that
actually slow down the read/write modes for CAS3 but this then allows a
faster FSB but not necessarily faster data transfers??? Or have I just
screwed up the concept of CAS Latency in general?
    And while PC133 were in general a little faster than their PC100
counterparts, with the PNY it was just the opposite although not by much.
Since my LX boards are sometimes a little picky on memory (despite being a
66MHz bus), I find these correlations of great interest.

  And speaking of these dual Pentium LX boards, I'm still looking to put
some more processors in them. Since a lot of people may have upgraded their
BX boards to faster Pentium 2 chips at 100MHz, does anyone have a source for
some used 300 or 333MHz PII chips? I figure with the faster Celerons running
at 466MHz under $100 and the Via Joshua soon to be released (this
Tuesday???) that a used PII running at 66MHz should be relatively cheap. And
I definitely need inexpensive parts to finish my 9 PCs for the LINUX

Thanks!  Randy Hofland

Derek Martin wrote:

> Randall Hofland wrote:
> >
> > OK folks!
> >
> > Just when I thought I understood how to figure out just how fast my PC
> > memory was, I read a review ( that shows CAS3 DIMMS are
> > faster than CAS2. Any thoughts or explanations since CAS2 seem to be
> > more expensive???
> A quick look at one of the pages you provided links to shows that the
> faster CAS3 RAM is rated at 133MHz, where the CAS2 RAM is only 100MHz.
> That explains the speed difference.
> As for CAS3 being cheaper, I can only guess that the reason is a lack of
> demand, since most Ix86 chips and clones aren't intended to be run at
> higher than 100MHz, and most people don't overclock.
> Cool site though, thanks for the links. :)
> --
> PGP/GPG Public key at
> Derek D. Martin      |  Senior UNIX Systems/Network Administrator
> Arris Interactive    |  A Nortel Company
> derekm at  |  dmartin at
> -------------------------------------------------
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