🚀 go-pugleaf

In article (well, I don't know what article really, it arrived and
disappeared while I was on vacation) someone writes:
>> How do I know someone didn't give me 150ns SIMMs either accidentally
>> or because they figured I'd never know?
>
>Funny you should ask...
>   Look at the individual memory modules (chips) on the SIMM boards. Up
>in the top right corner of the chips there should be a speed rating. "-15"
>means 150ns. "-12" means 120ns. "-8", unsurprisingly is 80ns. These methods
>of marking have been consistent with all of the SIMMs that I have seen, though
>I am not certain that yours will have the same markings (but more likely than
>not, I think).

A better method is to check the back of the SIMM for a -15 or -12 or
whatever.  Manufacturers such as TI and Toshiba speed-test the SIMMs after
assembling.  A SIMM made of all 120 ns chips won't necessarily meet 120
ns specs.  I've seen SIMMs with all 120 ns chips marked -15 on the back
(and had them fail in testing that required 120 ns SIMMS), and I've seen
SIMMs made with a mix of speed chips.

A lot of "garage" operations (like mine), don't speed-test the SIMMs
they make.  I just buy faster chips than are needed (nowadays I only
buy 80 ns chips).  On a Mac Plus, 200 ns SIMMs would be fast enough.
Steve Ligett       steve.ligett@dartmouth.edu or
(decvax harvard linus true)!dartvax!steve.ligett