Any way to modify high-density 256 MB RAM?

[jtr1962]

I purchased two sticks of 256 MB PC133 SDRAM at CompUSA today. Though the machine I plan to put them in needs more RAM like I need a hole in the head(it already has 768 MB), the price was right at $9.99 each after rebates, so I figured what the heck, even though it meant I'd need to remove two 128 MB sticks to make room. The SKU number is the same as the last 256 MB RAM I purchased from them, so I thought no problems. When I got home and opened the package, I noticed it only had chips on one side. Unfortunately, there was really no way to tell when I purchased it due to the way it was packaged, or I would have had second thoughts. Also, the package said 100% compatibility guaranteed, which I know isn't true but that means it should work in most machines. I figured maybe they configured the board so it would work in a machine that only supports 256 MB per slot, like my AX6B based PII-450. Anyhow, the machine read the memory as 128 MB, which really didn't surprise me. Basically, this RAM is far from 100% compatible as the package says. Any Intel-based machine more than a year old probably wouldn't recognize it as 256 MB, and that's a lot of machines.

Now I'm left with three choices-get my money back(and hope I don't pay an open box fee on the one opened package), exchange it for something compatible(must be the same SKU number and price so I can get my rebate or I'm not interested), or sell them on eBay. I'm not thrilled with any of these options as they all involve more trips and/or extra work on my part, and except for the second one, will leave me in the same position I was in before I purchased the RAM.

CompUSA is really at fault here for not mentioning that this RAM was high-density, or I wouldn't have wasted my time buying it. If I don't get any satisfaction, I plan to let them deal with the proper authorities like Consumer Affairs, The Better Business Bureau, and my local newspapers. Hopefully, a lot of people will have the same problem I did and they won't repeat this. I'm guessing they mght be doing this as part of a bait and switch. The customer buys the incompatible RAM at the low price, returns it, and is offered much more expensive "compatible" RAM. I saw someone there purchase 2 128 MB sticks of generic PC133 at $40 each since the salesman told him that the 256 MB might be incompatible in his machine. I was ready to tell the guy he was being ripped off but thought the better of it. Next time I wouldn't hesitate. Naturally, if they try to sell me "compatible" 256 MB RAM at $50/stick if I go back I'll tell them where they can put them. I really don't need the RAM at all, but was only getting it because it was dirt cheap.

I'm looking for a fourth choice. Can the RAM be jumpered, or otherwise modifed to work in a M/B like mine. The 256 MB sticks that work read as two rows, four banks. These ones read as one row, four banks. It might be something as simple as cutting a trace and soldering the cut trace to another pin, or maybe not. I haven't found anything online about doing this, so I thought someone here might be able to point me in the right direction.

 

[me]

Well ... it's not like I have any clue about high density versus non high density RAM (I still use presence-detect SIMMs), but if this is CompUSA, I think you're giving them too much credit to be doing some sort of complex bait and switch deal. The fact that one employee there perhaps knew better doesn't really change that.

If the packaging states 100% compatibility and they don't work in your system, then take them back. They won't charge you an "open-box" fee if the packaging states they are guaranteed to be 100% compatible. If the minions object, calmly ask to talk to the manager. There's no way anyone with two frontal lobes could fault you on a situation like this.

Then again, if it were me, I'd throw them in my glove box and use them as emergency windshield ice-scrapers. At $9.99 each, despite what might have been written on the packaging, I would only have bought them with a 50/50 expectation of actual functionality. I wish I had access to RAM at that price, even with 50/50 odds on it actually working. (No, I don't want to buy yours. :wink: )

 

[Cliptin]

This sounds like a problem of single vs. double sided RAM.

Why not look up a compatible part number on crucial.com and then find the crucial part number on pricewatch or ebay?

 

[Tea]

This is an issue that arises with monotonous regularity, JTR. This thread over at the other place discusses it, albeit from a slightly different standpoint.

Seems to be our day for re-doing all the old FAQ questions. Tannin did the disk copy one this morning, guess it's my turn to do the RAM one tonight. (Besides, I need the post count more than he does - I'm the only one amongst us who never got to 1000 posts.)

Doubtless one of the real RAM gurus will be by in due course to explain it all using the proper terms and in great detail, but for now, I'll just stick to my usual "to hell with the theory, this is what actually works" point of view. And muddle up my SIMMs and my DIMMs because I get lexdixic sometimes.

1: RAM speeds are a limit not an absolute. There is no reason at all why you can't run PC-133 RAM at 66MHz. The 133 is a limit - you can't run it faster than that, but you can run it as slow as you like. (Overclocking aside, of course.)

2: The actual causes of RAM compatibility issues are highly technical - and I mean seriously technical. Unless you are a main board or memory engineer, don't even try to go there. To the best of my knowledge, there is not an SR member who can properly answer questions like: "I bought a Crucial PC-133 but it doesn't work in my motherboard. When I put it into my friend's board, it worked fine. But my board works OK with this stick of Hynix."

But the practical upshot of RAM compatibility is very simple. Some RAM works in some boards, some RAM works in other boards, some RAM almost never works, and some RAM almost always works. Sometimes you can mix RAM, sometimes you can't mix RAM. Some boards are fussy about RAM, some boards are forgiving about RAM.

Always be prepared to mix and match till you get a working solution. If you want to avoid mixing and matching as much as possible, buy the best brand of RAM you know of, be prepared to pay a little more for it, use quality main boards, wear the red sock on your left foot, and go to church regularly. If you don't want to ever have to bother messing around with trial and error RAM matching, go to a decent computer shop and pay someone like me to do the job for you.

3: I see that the famous size-detection furphy is still doing the rounds. Arctic Chicken, you ain't the first one to have been told that horsesh*t, and you won't be the last. Full marks for guessing that your informants were "not too bright".

The actual cause of the size-detection problem has nothing whatsoever to do with the RAM being PC-66 or PC-133 or PC-298.7 for that matter. It has to do with the size of the RAM chips (as opposed to the size of the SIMM itself). (Quick disclaimer: this is an oversimplification - it actually has to do with the addressing mode of the RAM module and the way it translates RAS and CAS signals - but you'll need one of the SR RAM gurus to explain that properly. For our current purposes, my brute force explanation will do.)

Your old main board is expecting to see 16Mb chips - note the small "b" - that's Megabits. A standard 16MB RAM module has 8 x 16Mbit chips = 16MBytes. A standard 32MB module is the same except that it's double-sided: it has 16 x 16Mbit chips = 32MByte.

Now, you take a nice shiny 64MB module and plug it into your old main board, and the board "sees" 8 chips. Ahah!, it says, 8 x 16Mbit = 16MByte! Most 64MB SIMMs use 8 x 64MB chips, and the poor old motherboard gets confused. Plug in a 128MB module and it sees 32MB. And so on. And your friendly local not very bright self-appointed technician looks at the old, working-just-fine 32MB DIMM which dates back to PC-66 days, and then he looks at your shiny new PC-100 64MB DIMM, and he tries another old PC-66 32MB DIMM he has lying around, which works fine of course (this sort of person always has a lot of old, crappy, work-some-of-the-time stuff lying around, and will usually try to sell some of it to you at about twice the market value if you are unwise enough to stand still for too long) - but the 64MB DIMM is only recognised as 16MB and his bloodshot eyes light up with the wonder of discovery. Ahah! he shouts, I have made an inven ... an inventor ... an inven-whatever it is you call it where you discover something new and prove how clever you are! You need PC-66 memory to work in an old main board! Please give me more of your money now.

There are some exceptions. Some 32MB SIMMs used 4 x 64Mbit chips instead of 16 x 16Mbit. They are easy to recognise. And these, of course, won't work in your old board either. They come up as 8MB, or else don't work at all. Most of these 4-chip 32s (which were manufactured later than the 16Mbit chips, of course) are new enough to be marked as PC-100 or even PC-133. Your local semi-bright electron-monkey, if he sees one, will hold it aloft as definate proof that his theory is Holy Writ. And there are some 64MB parts that will work in your old board: they are called "double-sided, double-high", and they are massive, strange-looking things that are essentially two standard 16-chip 32MB SIMMs mounted one on top of the other - so forget getting one of these into a desktop case. They are very rare. In my 20-something year career, I have seen exactly three of them.

 

[jtr1962]

Thanks for the feedback everyone. As best as I could tell from looking up things on various sites, the problem is that the single-sided memory uses 8 RAM chips configured as 32Mx8 versus the double-sided ones which have 16 chips of 16Mx8. The M/B chipset needs to be able to address 32Mbit RAM chips in order to be able to use single-sided RAM, and the 440BX in my machine can't, or the machine would obviously have a maximum capacity of 2GB in it's four SIMM slots instead of 1 GB. The just of it is that I can't think of any way to modify the SIMM to work based on this explanation since it is akin to changing the internal structure of the RAM chips, which I obviously cannot do. Since I've done a few things that even the experts said weren't possible(like getting a 2.88 MB P/S2 floppy to work in a regular PC), if even I can't think of a way to modify these SIMMs, then it probably can't be done. Here's as good an explanation of the situation as I could find:

http://www.oempcworld.com/generic46.html

Another place mentioned that it would be possible to have compatible single-sided SIMMs if xy addressing(whatever that is) where implemented, but since there were no technical advantages to doing so, no such RAM chips exist. Too bad I forgot the link.

Since the package does say 100% compatible, and I had no problems last time I bought this exact SKU number, I had every right to expect it to work, and therefore should have no trouble returning it. Of course, I could hold on to them for whenever I purchase a new M/B that can use them, but knowing me if I have a M/B that can use 512 MB SIMMs, then I'd max it out with those. You can never have too much RAM(or storage for that matter).

 

[jtr1962]

Why not look up a compatible part number on crucial.com and then find the crucial part number on pricewatch or ebay?

The lowest price on pricewatch for something compatible is $21 last I checked. The only reason I bought this RAM was because it was only $10. Remember that I need to remove 2 128 MB modules to make room for the 256 MB ones, so I'm really only gaining 256 MB by doing this, even though I'll wind up with 2 spare 128 MB modules that I can (eventually) use in a Linux box I plan to build with some spare parts. Thus, $10 per SIMM is my limit. With 768 MB already in the machine, it's not like I actually need the memory at this point(well once or twice I actually did). CompUSA has 256 MB on sale this week for $12.99 each after rebates. If it's compatible hopefully I can talk a salesperson into a straight exchange and I can still get my $15 rebate using this week's rebate slip. I'll probably go there tomorrow and I'll keep everyone posted on what happens. It's a $%#@! 5 mile walk each way since I'm too cheap to pay for the bus and subway, so I'm really annoyed that I even have to do this. Once was good exercise, twice in one week is torture. :evil:

 

[Mercutio]

Five miles, in New York, in winter, and not that far from the icy depths of the Atlantic?

I guess $5 for two cab rides is rather extreme for a $10 memory module but I think we'd all forgive you if you hopped a bus.

 

[jtr1962]

Five miles, in New York, in winter, and not that far from the icy depths of the Atlantic?

I guess $5 for two cab rides is rather extreme for a $10 memory module but I think we'd all forgive you if you hopped a bus.

I actually love walking that far in the winter(I can do five miles in under an hour), just not twice in the span of three days. It was about 35°F when I went on Friday, and I was sweating a bit by the time I got there believe it not. Doing it in the summer is the real pain. Too bad they don't have any kind of decent bike parking in the store or I'd go that way. 5 miles by bike would take me under 15 minutes if I don't run into traffic. The problem is that it's highly likely the bike won't be there when I get out of the store, even if I chain it up to a pole. My brother had two bikes stolen that way on Queens Blvd., which is where CompUSA is. The bus is $1 off-peak, so maybe I'll walk there and take it back if I feel my feet giving out. Sometimes your body can do more than you give it credit for. This past August I made my mom walk with me about 5 miles in lower Manhattan only 3 months after her hip replacement, and she said she felt the better for it.

 

[Tea]

I understand about the importance of saving money, JTR. I learned about "a penny saved is a penny earned" when I was just little, and now that I have Tannin's credit card to rely on, rarely fail to ignore economy where this is possiblle.

Back when Tannin was still saving up to buy the shop and money was tight, he used to head off to the office early very every morning, and because I liked to make myself useful, most days I'd come in a little later to help out, usually arriving about morning tea time, staying for lunch, and knocking off after afternoon tea. Knowing that Tannin was short of money, instead of taking a taxi, I used to catch the bus. This way, I only needed 50c each way (instead of $5 a trip) when I came in to help out with lunch ... er ... I mean work.

Anyway, one day I thought I'd help out even more with being economical, and instead of catching the bus to work, I just ran alongside it all the way to the office. I was very proud of myself as, still panting, I helped myself to a chocolate pudding and told Tannin what I'd done and how much money it saved. He clipped me over the ear and said,

"You fool! If you'd have run alongside a taxi, you could have saved five bucks!"

I have since signed the pledge and sworn never to be economical again.

 

[James]

Now, if you're looking to sell the sticks...

 

[jtr1962]

I helped myself to a chocolate pudding and told Tannin what I'd done and how much money it saved. He clipped me over the ear and said,

"You fool! If you'd have run alongside a taxi, you could have saved five bucks!"

I have since signed the pledge and sworn never to be economical again.

I can only imagine the sight! I don't suppose you would have been able to ride a bike instead. I'm not sure if an ape your size would be too comfortable on a normal sized bicycle.

Tannin made a good point, though, and I'll add another. Never, ever be economical if it affects your health in any way. No sense running if you end up in the hospital with a heart attack, now is there? :mrgrn:

 

[jtr1962]

Now, if you're looking to sell the sticks...

I didn't return them yet, so if you or someone you know are interested in buying them let me know. I'm probably going to CompUSA tomorrow but I'll check this thread and my PMs before I go. I imagine shipping to Sydney would be a bit pricey though.

 

[James]

Yep, would you take what you paid for them plus postage, or would you like to make a little profit?

 

[LiamC]

Tea, an absolutely outstanding contribution

Any chance you will post that on Red Hill so I can link it? Or could I host it with suitable acknoledgements and links? I get asked that so many times it is not funny.

FWIW, I believe that the answer is in the number of address lines on the motherboard and is a design decision. The manufacturer decides what density modules will be supported and address lines are used to suit. Higher density chips have more address lines but like the 5th multiplier line (L3 bridge) in KT266A motherboards, it is/they are never seen.

I wish to make a contribution to memory FUD (Bank interleave) too

http://www.realworldtech.com/page.cfm?AID=RWT110401204523

There are a couple of minor errors and one day I'll get around to correcting them...

 

[Tea]

Thanks Bill (#2). I'm glad you liked it. I don't really see what it has to do with memory interleave though, but by all means use it if you want to,

(Fool! He means the other thing you wrote, about PC-66 and PC-133 RAM, you stupid ape.)

Oh.

(Well, there is no need to be rude about it, you ... you, you, human!)

Ahh, it might be more practical if you were to take it, adjust as needed and host it yourself, Bill (#2). In the old days, when Tannin was less grumpy and more energetic, he might have turned it into an all-singing, all-dancing page on the Red Hill site, but he's probably not really up to it now.

(And what's this '#2' nonsense? Another of your stupid ideas?)

(It's not stupid. How else am I suppozed to remember which one is which?)

(You could use their names.)

(But they are all 'Bill'! Or most of them, anyway. First there was Bill the Flagreen, then there was Bill the LiamC, and now we discover that Dozer is another Bill! There are probably more of them in the woodwork too.)

(Now you are being ridiculous. What's wrong with being Bill?)

(Nothing! I like Bills! I'm just trying to impoze a little order on the zituation with a perfectly rational, zenzible zcheme of giving each new Bill a number! What could be zimpler, you ztupid human?)

(OK, OK. Keep your fur on. No need to shout.)

(I wazn't zhouting.)

(So why are you talking funny?)

(I'm not talking funny. I'm perfectly rational, and az calm az you - I mean as calm as you are.)

(Hmm...)

 

[LiamC]

Hey, I'm with Tea. I run for the hill when I see another bill in the post!

 

[Cliptin]

I like green bills; but I don't like to see Bill green.

 

[Will Rickards WT]

Then there are the Will's which is just another derivation from William. For my son (who is the 4th) we chose the nickname Liam which I believe is a typically Irish abbreviation for William.

 

[Clocker]

A friend of mine at work had a similar problem with his old Dell computer (P2-266). System would not boot with the new PC100 memory he bout for $10/128MB stick (after rebate). All he needed to do was update the BIOS on the machine so it was compliant with SPD1.2 memory and it worked fine after that.

C

 

[jtr1962]

It's definitely a hardware problem. My machine is flashed with the latest BIOS(April 2000). I think that was the final version for this board. In any case, I don't think a BIOS upgrade would help since it's a matter of the chipset being able to physically address the RAM. BX chipsets just can't read all of a 256Mbit memory chip, which is the size used on single-sided 256MB RAM.

The memory CompUSA has on sale this week for $12.99 after rebate is also high-density.