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barney
May 27th, 2011, 02:01 PM
On a typical 286 motherboard, can I use any 30 pin memory type. I looked at the specs and it says it uses 1X9 30 pin but it doesn't state the speed. Can I use any speed: for example 60ns, 70ns or 80ns? What speed would be the most compatible?

Thank You

Unknown_K
May 27th, 2011, 02:14 PM
Even 80ns should work. PC systems like parity RAM (9 chip or 3 chip), Macs like non parity (8 chip or 2 chip). Generally you find the last batch of 30 pin SIMMs mader were the fastest (60ns) and older sticks are slower (70-80ns).

barney
May 27th, 2011, 02:43 PM
So, I take it I can use any type (60, 70, 80 or 100ns)?

Also is there really any noticable difference using 60ns vs 100ns on a 286?

dorkbert
May 27th, 2011, 02:59 PM
I would think you can use up to 100 ns parts.

Unknown_K
May 27th, 2011, 04:23 PM
I would not use anything over 80 and it does depend on the 286 speed. Only the last generation 286 boards used 30 pin SIMMs (most had DRAM on the board and some had SIPP memory). They made 286 processors in speeds from 6 or 8 to 25 Mhz, the faster chips probably needed 70ns RAM.

Druid6900
May 27th, 2011, 07:09 PM
One thing to remember is that all the SIMMs should be the same chip count (don't try and mix 3 chip and 9 chip in the same bank) and the speed of all the SIMMs should be the same. I know that sounds obvious, but, if you're not used to working with this old technology, it might not be so obvious.

FishFinger
May 28th, 2011, 01:44 AM
There are no hard or fast rules for matching SIMMs. The number of chips doesn't matter, only how they're connected to the address pins.

It's pretty much pot luck whether non-matching SIMMs will work together as a pair/four.

Druid6900
May 28th, 2011, 08:00 PM
Let's just say that you'll be better off taking heed of the advice I gave to avoid a situation where a particular board doesn't like different chip counts within a bank, shall we?

tingo
May 29th, 2011, 01:07 PM
Not to mention EDO vs. FPM SIMMs. One older Compaq actually worked with a mix of EDO and FPM, but it complained every time you booted it about a memory mismatch, and you had to press a key to continue.

FishFinger
May 30th, 2011, 01:44 AM
Let's just say that you'll be better off taking heed of the advice I gave to avoid a situation where a particular board doesn't like different chip counts within a bank, shall we?

Except that advice would be wrong.

Chip count is nothing to do with whether unmatched SIMMs will work together or not, and means nothing to the motherboard. There are two or three common combinations of how the address pins on the chips are mapped to the pins on the SIMM board, and as long as they all match within a bank they will work together. A 1MB SIMM could have eight 1Mbit chips, or two 4Mbit chips, and as long as they're all connected the same way they will work. Chip count doesn't come into it at all.

Druid6900
May 30th, 2011, 07:40 PM
Fine, have it your way, I don't really care enough to get into a pissing contest with you.