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What type of RAM is this? Need to buy some for my 486.

DeathAdderSF

DeathAdderSF

Experienced Member
Joined
Jul 2, 2016
Messages
317
Location
USA
Hello.

I have an AST Advantage! 486/25. I want to upgrade the RAM to max, but I don't know which chips to buy.
If someone could have a look and let me know the type I need, I'd appreciate it. Thanks.

ram2.jpg

(click to see the full-size photo)
 
Oh, that's too bad. It's going to be quite difficult to find those, I think, considering it's a non-standard size. D'oh! :(

But thanks for clearing it up.
 
NeXT said:
No problem. I just didn't want you to go and buy the ram and find out it didn't fit.
Click to expand...

Yeah, I appreciate that. Even though this old RAM is pretty cheap nowadays, I still wouldn't want to waste any money on the wrong kind.
And now begins the search for the correct RAM. Damn them for using an uncommon size!!
 
Looks like SIMM to me too, there is normally a marking on it though, for example ours is stamped 2SIMM indicating its a stick of 2mb SIMM.... Will have another look at it tonight to confirm, but agree for now that it looks like SIMM memory... :)
 
NeXT said:
NO IT IS NOT!

Count the pins. That's a 64 pin SIMM. AST used a proprietary SIMM in some of their 386 and 486 machines. The Macintosh IIfx did the same but those are not electrically compatible.
Click to expand...


Hi! Other than actually counting the pins... how can you tell? Is there a distinguishing characteristic of it that makes it look different than a 72pin SIMM chip?

Thanks!


On a side note, the only other thing I can add here is that the ram is 70ns ram. If you (the OP) wants to also improve performance, look for 60ns ram chips. Those were treated like gold back then. You could also (in some rare instances) find 55ns and 50ns RAM chips. But I've only run into a couple in my entire life... they're almost unobtainium... (at least they were back then).
 
It looks like there may be a pin count on the RAM, but I can't tell. All I see is a 1 near the first pin. I can't see the last one, though.
 
I bought an AST 486 expansion board on eBay and yanked the RAM. It's the correct 64-pin kind, and was useful in doubling the ram on my 486/25.
The websites that list the 72-pin RAM as being compatible are incorrect.
 
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