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Soviet Conscript
06-14-2010, 05:58 PM
well i've been wanting to upgrade my one old 486's ram from its 8mb (8x1 mb sticks) to something more.

anyways i've had no luck finding the 30 pin ram i need at a reasonable price so awhile ago i bough a big baggy full of random 30 pin ram for a good price. problem is i have no idea what size any stick it.

i've kinda been randomly putting the ram in to see what comes up, i almost always get a *beep* and nothing which i assume is ram error, sometimes it sounds like its botting up fine but i get no display and one i managed to get....1mb which means i found a good combo but all those sticks must of been 256k sticks.

anyways is there a device that can tell you how much ram is on a stick? or some visual method. it doesn't help these old MB's are picky about ram type/size combinations and what slots there in.

Kitsune Sniper
06-14-2010, 06:03 PM
Uh, you shouldn't just stick random sticks in a computer, they may not be supported and might damage your RAM slots.

The best way is to look up the codes on the sticks themselves using Google. Most of the time you'll get hits from online RAM storefronts which list the product code, manufacturer, timing and voltage ratings. You can then use that info to find out which of those will fit on your motherboard.

Soviet Conscript
06-14-2010, 06:23 PM
Uh, you shouldn't just stick random sticks in a computer, they may not be supported and might damage your RAM slots.

The best way is to look up the codes on the sticks themselves using Google. Most of the time you'll get hits from online RAM storefronts which list the product code, manufacturer, timing and voltage ratings. You can then use that info to find out which of those will fit on your motherboard.

i know its a bad habit but in 20+ plus years of doing that kinda trial and error i never had an issue where something burned out. and were talking putting in cpu's under the wrong voltage and plugging in AT PSU's incorrectly, i suppose i'm just lucky.

i'll try this but on alot of these ram sticks there very little info.

Ze_ro
06-15-2010, 02:19 PM
Actually, you're probably pretty safe with 30-pin RAM, I don't think there were many different varieties there, and even if the timing isn't quite right, I don't think you're likely to damage anything. If you're really concerned, maybe find an old 386 board that's expendable. Keep in mind that a lot of motherboards require you to insert the RAM in matched pairs, so if you're just sticking random chips in all eight slots, it might have a hard time recognizing it, even if they're the same size. Even if your motherboard isn't as picky, if you have different sized RAM in two slots, it'll sometimes only recognize the smaller size (so if you have a 256k chip and a 1MB chip, it might just tell you that you have 512k).

Your best bet is to try to sort through your bag and try to find matching sets, and insert each set at a time to see what it is. Make sure you label them afterwards so you don't have to screw around with this again in the future!

As Kitsune mentioned, looking up part numbers on the internet is another way. Keep in mind when you look up individual chips, you'll have to count the chips on the memory itself, and spec sheets are notorious for using confusing notation when listing RAM sizes (like, they'll say 8 x 16k, and you won't be able to tell if the chip itself is 16 kilobytes (or maybe kiloBITS) and is meant to be in a set of 8, or whether the chip itself is 128k and has 8 divisions internally).

--Zero

Soviet Conscript
06-15-2010, 11:23 PM
gone through most of them and the vast majority are 256k and 1mb sticks. the last couple seem to allude me though as i can't find any info.

blah, i never thought finding a measly 32mb of ram would be so hard.

Jorpho
06-15-2010, 11:45 PM
Have you checked the manual of your 486's motherboard to see if there is actually some specific combination it will accept to get 32 MB of RAM? I doubt it will be as simple as two sticks of 16 or four sticks of 8, if it is possible at all. (32 was an awful lot of RAM in those days.)

Arkhan
06-16-2010, 01:05 AM
pft. with all them old boards, if it fits in the slot, it probably wont break it unless you leave it on for prolonged instances.

a minute or two wont do nothin

Ed Oscuro
06-16-2010, 01:22 AM
My first thought is to take any label numbers and run them through The Google. I've been surprised to find that many old RAM stick part numbers (or other random numbers on there) bring up matches in Google. I don't know how helpful running the numbers right off the individual RAM chips would be, though it might give some of the information. Likely just the individual size - which you'd multiply by the number of chips per module to get its actual size.

Question time:

Are the old motherboards smart enough to run the RAM at a lower speed if you mismatch (i.e. one module specc'd higher than the other)?

Also that could be a problem - potentially - if you have a bunch of sticks, there may be two (say) that seem to work right, but you'll have no idea of the speed. If you're looking at 16MB sticks you probably won't find anything timed slower than the 8MB it came with - then again...

There may be an old DOS application or something to suss out the timings if they aren't labeled.

Jorpho
06-16-2010, 07:49 AM
I've never even heard of people talking about SIMM timing. Did that vary at all?

Soviet Conscript
06-16-2010, 11:31 AM
Have you checked the manual of your 486's motherboard to see if there is actually some specific combination it will accept to get 32 MB of RAM? I doubt it will be as simple as two sticks of 16 or four sticks of 8, if it is possible at all. (32 was an awful lot of RAM in those days.)

yhep, it accepts 32mb ram as its max. i also tried various ways it says it wants combinations. i've figured out the bulk of the sizes through various means, looks like none are over 1mb so i'm back to my search

Ze_ro
06-16-2010, 07:24 PM
gone through most of them and the vast majority are 256k and 1mb sticks. the last couple seem to allude me though as i can't find any info.
Unfortunately, this seems to be the case when you find large numbers of sticks. I have a whole bunch of useless old chips myself. For what it's worth, I've found that newer memory is more likely to actually have an manufacturers label on it that says the size... so if you're looking through random RAM at thrift stores, poke through the bags and if there's nothing labelled at all, and none of the boards have many chips on then, then it's probably all garbage.


I've never even heard of people talking about SIMM timing. Did that vary at all?
It did... though I'm really not sure how much of an effect it had. I still need to get more RAM for my Mac, and I read somewhere that it had to be 80ns or better. I've also seen RAM timings listed for Amiga stuff. I've dealt with a lot of random PC motherboards in my days, and I've never had a problem with this though. I have no idea what would happen if your RAM is too slow... maybe just random memory errors or something.

--Zero

Jorpho
06-16-2010, 08:36 PM
It did... though I'm really not sure how much of an effect it had. I still need to get more RAM for my Mac, and I read somewhere that it had to be 80ns or better. I've also seen RAM timings listed for Amiga stuff.A difference between Mac and PC RAM I would definitely believe.

kedawa
06-16-2010, 08:49 PM
Apple has never used anything proprietary for RAM. Certain varieties of RAM may not be compatible with any Apple products, but any RAM you find in an apple computer is standard stuff.

Neb6
10-04-2013, 04:01 PM
For SIMMs with 8 or 9 chips, take a look at the numbers written on the chips themselves.

The old SIMMs used to sometimes list the capacity in the number on the chip. For example, each of the 8 chips on a 256K SIMM would have something like "D41256-12" written on it. Or maybe "D41256-120". The "256" was the clue as to the capacity of the SIMM. Unfortunately, they eventually threw that system out the window and went to a totally confusing numbering scheme.

If it has 8 chips, it's non-parity.

If it has 9 chips, it's parity enabled.

The number at the end (after the dash) is the speed. If you see -12, it likely means 120NS. A -6 or -60 would indicate that it's a 60NS SIMM.

And if the numbers are totally weird, check the fiberglass that the chips are embedded in. The capacity might be inscribed on it.

Finally, an alternate way to do it is to plug the RAM into your PC and read the total RAM count on startup. Since you're using a 486, you'd need to install four 30-pin SIMMS (or one 72-pin SIMM -- if it has 72-pin slots). If installing four identical 30-pin SIMMs, just divide the RAM total that shows up on the monitor by 4.

Oh, and no worries about plugging in mis-matched RAM. It won't harm your computer.