SUMMARY: Classic/LX memory - type and speed?

From: Syed Zaeem Hosain (
Date: Thu Jul 01 1993 - 12:20:34 CDT

Hi, folks.

Thanks to Jim Seavey (Jim.Seavey@West.Sun.COM), I have the definitive
answer to my question sent out earlier:

> Hi, everybody.
> This is a general quick query about what kind and speed of memory is
> installed in the Sun Classic and LX.
> 1) Is the organization of the SIMM unusual? I.e., is it 4MBx9 like the
> SS2 and PC standards, or is it one of the more odd-ball arrangements
> like the IPX and ELC?
> 2) What speed SIMM should be used for the Classic and LX? Since the
> speed of the processor is 50Mhz, and it has little or no cache, I
> assume that the memory needs to be faster than what would be used in a
> SS2, so I assumed 70ns at least, but ... I would like better info on
> this.
> Thanks!

1. The memory organization is similar to IPX - must be 1x33. And
   the size must be either 4MB or 16MB SIMMs.

2. As mentioned above, you can either use 4MB SIMMs or 16 MB SIMMs,
   but they must be installed in pairs. So valid configurations
   are slightly more restricted than would be usual - see next item.

3. There are six SIMM slots. Thus with 4MB SIMM, you get 8, 16 and
   24 MB total memory, and with 16MB SIMM, you get 32, 64 and 96 MB
   total memory in the box. I suppose you could mix SIMM sizes
   (only in pairs) for other combinations (this is my guess - not
   input from Jim).

4. The speed typically should be 60ns for the Classic/LX and 70ns
   for IPX. Thus the Classic/LX memory can be used in the IPX but
   not vice-versa. I have found out from another source that 70ns
   will also work just fine in the Classic/LX and 80ns will work
   just fine in the IPX (my personal experience says this is true
   too - my IPX has both 70ns and 80ns memory and works fine). In
   addition, George Ross noted that the the SunExpress catalog
   lists 70ns SIMMs for the Classic/LX.

Thanks also to others who responded: (George D M Ross) (Matt Mauss) (John Justin Hough)

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