X20 Memory

[whizkid]

In case I continue with my X20 restoration, it can use some RAM. I know it wants PC100 SO-DIMMs, and I have two questions for the experts:

1. Will it use high-density (8-chip) PC100 256MB memory?

2. Will it use PC133 memory? (The 600E will use PC66 and PC100, so I know some ThinkPads aren't too fussy.)

[monty cantsin]

In case I continue with my X20 restoration, it can use some RAM. I know it wants PC100 SO-DIMMs, and I have two questions for the experts:

1. Will it use high-density (8-chip) PC100 256MB memory?

No, it won't, only low-density. Has the same i440BX chipset like the TP T20,21,22, 600/E/X, 570/E, 240/X etc.

2. Will it use PC133 memory? (The 600E will use PC66 and PC100, so I know some ThinkPads aren't too fussy.)

It's better you stick with the PC100 modules. I've personally seen a PC133-labeled stick that worked, but the right ones are so scarce that finding one is almost like breaking the jackpot in the lottery. I think it's best to purchase exactly one of the sticks that IBM recommends for your notebook, numbers 33L3069 and/or 33L3070. They usually go for about 60-80 USD on ebay.

Btw, have a look at this auction:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... eName=WDVW

http://www.samuelan.com/online/ibm256_07.jpg

http://www.samuelan.com/online/ibm256_08.jpg

The front of this module is labeled as IBM and says it's a PC100 CL3, on the back there's another IBM label, but also a Micron sticker reading PC133 CL3...

[whizkid]

Very interesting indeed. It seems IBM's own 256MB part is 133MHz.

And here's another shocker: While getting ready to sell my X20, I downloaded and ran PC Doctor and put it through all the tests. When I asked it to scan the memory system, it said that the largest capacity supported was 512MB!

That can make a HUGE difference if a lot of (bloated) applications are running at once.

Any daredevils out there care to try a 512MB PC133 part in his or her X20? Do such parts exist? ... Sure enough, Crucial has one for $116, only $16 more than the 256MB part.

[skanky]

ive just ordered a 512mb pc133 stick o ram from ibm for a user here at work, they're on a x24 i think but will let ya know how that goes..

[whizkid]

1. Will it use high-density (8-chip) PC100 256MB memory?

No, it won't, only low-density. Has the same i440BX chipset like the TP T20,21,22, 600/E/X, 570/E, 240/X etc.

Tawbook says the X20 and X21 use the 440ZXM chip. Intel has info on the 440ZX (nothing on 440ZXM). The data sheet http://www.intel.com/design/chipsets/da ... 065001.pdf says it's for the PII, not PIII. Can handle up to 256MB with two DIMMs (guessing 256MB each), but will handle single and double density.

So it looks like Intel is saying that 256MB hi-density PC100 should work. And yet IBM sells PC133, and PC Doctor says 512MB should work.

Strange. I'd try it if I had the parts. I'll just sit here and wait for test results!

[monty cantsin]

Very interesting indeed. It seems IBM's own 256MB part is 133MHz.

Yes, it is a 133Mhz part, but one of the very rare lo-density kind (16chips). As I said before, the Mhz rating does not really matter, it's the internal organization (lo- vs. hi-density) that counts. But most PC133 sticks are hi-density, so it doesn't make much sense to look out for them, as the bus only works at 100Mhz and there aren't any performance benefits, anyway.

And here's another shocker: While getting ready to sell my X20, I downloaded and ran PC Doctor and put it through all the tests. When I asked it to scan the memory system, it said that the largest capacity supported was 512MB!

No, it's no shocker at all, but absolutely logical. The i440BX supports a maximum of three slots, each equipped with a 256MB module at maximum, which results in a maximum total memory of 768MB. The i440ZX, the offshoot of the i440BX that's used in the X20 and X21, only supports two slots and thus 512MB at maximum. As the X20 just has one memory slot that can be configured by the user (the other socket is formed by the 64MB on-board memory), the maximum memory for this machine is 320MB. Theoretically it could support up to 512MB (just as the 600E/X could support 768MB, theoretically), but because of the on-board memory, it's limited to much less in practice, of course.

Any daredevils out there care to try a 512MB PC133 part in his or her X20? Do such parts exist? ... Sure enough, Crucial has one for $116, only $16 more than the 256MB part.

As I said before, 256MB lo-density sticks are the maximum that works. These 512MB modules you referenced (which are only available as hi-density) will not run, under no circumstances! I can guarantuee you that, 100%.

[monty cantsin]

ive just ordered a 512mb pc133 stick o ram from ibm for a user here at work, they're on a x24 i think but will let ya know how that goes..

Sure it will work. The X22, X23 and X24 are all based on a totally different chipset than the X20 and X21. The i830MP in those machines does support hi-density sticks, so together with the 128MB on-board memory, you can reach 640MB RAM maximum with such a 512MB stick. But, I repeat, this won't work on the X20 and X21!

[monty cantsin]

Tawbook says the X20 and X21 use the 440ZXM chip. Intel has info on the 440ZX (nothing on 440ZXM).

Yes, an offshoot of the i440BX. The most striking difference for us here, memory-wise, is that with the i440ZX only two 256MB modules are supported, while the i440BX can handle three and (with buffered sticks) up to four. The i440ZX also lacks mobile support , but this is where the i440ZXM (for 'mobile') jumps in.

Can handle up to 256MB with two DIMMs (guessing 256MB each), but will handle single and double density.

So it looks like Intel is saying that 256MB hi-density PC100 should work.

No, certainly not! The term "hi-density" that's so common when talking about memory is actually technically wrong. When Intel speaks about "single and double density", this hasn't anything to do with those low- and hi-density called memory sticks.

http://homepage.hispeed.ch/rscheidegger ... 256MB_high

And yet IBM sells PC133,

Yes, but these are still lo-density ones!

and PC Doctor says 512MB should work.

Only theoretically. That means, if you would be able to replace the on-board 64MB for 256MB. There is not a single one 512MB stick out there that will run in a i440BX/ZX/ZXM environment.

Strange.

No, not at all.

I'd try it if I had the parts. I'll just sit here and wait for test results!

You're wasting your time.

[whizkid]

You're wasting your time.

Not at all!

I'm really enjoying myself. If I had the parts, I'd take five minutes or so and try it. I'm confident that it won't damage anything. At worst, it would not power on. It might say unsupported module... it might work (although I agree that's nearly impossible with the evidence so far). I'd still do it.

But then, that's who I am: somebody who tinkers with stuff like this for the enjoyment of just doing it.

So I don't think I'm wasting my time at all. This is how I choose to spend it. Similarly, I participate in forums like this. What a great thing!

[monty cantsin]

The data sheet http://www.intel.com/design/chipsets/da ... 065001.pdf says it's for the PII, not PIII. Can handle up to 256MB with two DIMMs (guessing 256MB each).

Actually no, this value, 256MB, is meant as a total maximum. Officially, according to Intel, only 128MB modules can be used with the ZX, but unofficially it supports the same modules like the BX, i.e., 256MB lo-density.

[monty cantsin]

You're wasting your time.

Not at all!

I'm really enjoying myself.

Well, I'm glad to hear you have a good time...

All I wanted to say is that you're on the wrong track here... using this chipset with that kind of memory is simply technically impossible. A much more promising start would be to try and find out how to exchange the on-board memory.

If I had the parts, I'd take five minutes or so and try it. I'm confident that it won't damage anything.

Yes, it wouldn't do any harm, this is true.

So I don't think I'm wasting my time at all. This is how I choose to spend it. Similarly, I participate in forums like this. What a great thing!

Ok, I think I got it!

[skanky]

just installed a stick of 512mb pc133 cl np sdram sodimm (p/n: 19k4656) on the user's x24, both bios and windows work fine and report the correct total of 640mb ram.

[whizkid]

Well, the X24 is a completely different machine. The X24 wants PC133 up to 512MB, so it's not surprising that it worked.

The X20 wants PC100 up to 256MB so I was hoping you already had that memory in an X24 and were going to try it in an X20.