Thinkpads Forum

I read all the posts in the sticky on this subject, and went to the Crucial website and ran their little utility to find the right memory for my 600x. They only list pc133 sodimms for it, but at $40. I can probably get pc100 on ebay cheaper than that, but I'm wondering what the deal is? If Crucial has 8 chip 133 sodimms that work in the 600x, why won't Microns or other ones that say they are "low-density" despite the fact that they are 8 chip not 16??

The 600X takes 100MHz RAM modules, i.e. PC100. If you can get 256MB PC100 modules for less than $40, I'd say do it - such things cost around EUR 40 or $54 plus shipping at the German Ebay site.

The only advantage I can see to the Crucial PC133 modules is that you can continue to use them if you upgrade to a computer with a 133MHz frontside bus. Otherwise there's no benefit.

As to why the others (supposedly) won't work on a 600X, my understanding is that the circuits on the RAM modules must be designed for access by both 100MHz and 133MHz frontside bus systems, and otherwise can only be used at the rated frequency.

I see a lot of misinformation on this subject in the German Thinkpad forum, and particularly at the German Ebay site... people claiming that only 16-chip PC100 modules work in a 600X, which is nonsense.

Another advantage with Crucial is that they guarantee their product to work in your machine or your money back.

hseaver wrote:They only list pc133 sodimms for it, but at $40. I can probably get pc100 on ebay cheaper than that

It's actually pretty hard to find low-density PC100 SODIMMs for under $40 shipped on eBay. Crucial's $40 is a very decent price.

pianowizard wrote:

hseaver wrote:They only list pc133 sodimms for it, but at $40. I can probably get pc100 on ebay cheaper than that

It's actually pretty hard to find low-density PC100 SODIMMs for under $40 shipped on eBay. Crucial's $40 is a very decent price.

Much easier to find them here in the marketplace for that price, actually. I've never seen one below $40 on eBay, although I haven't ever spent days looking.

Some recent eBay sales. Not all of them are PC100 modules but there's some good deals there.

rkawakami wrote:Not all of them are PC100 modules but there's some good deals there.

And not all of them are low density, right? The OP needs low density modules, which are more expensive.

Right. But here's one I quickly found:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 1015536532

Low density (4096 refresh cycles) $20 (shipped)

I found a pair of Samsung 256MB PC100 low density modules on Ebay for $55 delivered. It seems that auctions mentioning the IBM part number 33L3070 get driven up in price. Knowing the equivalent vendor part numbers and searching on them can uncover better deals.

Micron MT16LSDF3264HG-10Exx
Kingston KTM-TP390X/256
Samsung M464S3323BN0-L1L
Samsung M464S3323CN0-L1L
Qimonda (Infineon) HYS64V32220GBDL-8-C2

For the Micron part number the last two characters are the revision number and I search with those omitted from the search string.

I believe that the Infineon module HYS64V32220GBDL is a high density version. The first "32" refers to 32MB devices which will require 8K refresh cycles. The datasheet is available from here:

HYS64V32220GDL datasheet

Okay, just to document how some deals can be made...

Searched eBay using one of my favorite PC100 search strings (as BillP pointed out above) and bought this a few minutes ago:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0136969258

16 chip version (low density) with a non-DOA guarantee. We'll see how it works when I get it and run it through memtest86+.

edit: Sniped this one while I was in my way to work: http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0134562673

This one is a little more iffy since the only statement is "pulled from working system". But with the 100% feedback so far, I don't expect too many problems.

And getting back to the OP's original questions...

hseaver wrote:They only list pc133 sodimms for it, but at $40. I can probably get pc100 on ebay cheaper than that, but I'm wondering what the deal is? If Crucial has 8 chip 133 sodimms that work in the 600x, why won't Microns or other ones that say they are "low-density" despite the fact that they are 8 chip not 16??

Generally PC133 modules can be used in PC100 applications but there's a couple of things to watch out for. If the PC100 system uses CAS latency 2 (CL2) AND the PC133 module is CL3, then it won't work. Furthermore, there is a part on each module which contains information which is supposed to tell the computer what its capabilities are (size, speed, CL, etc.). This is known as the SPD (Serial Presence Detect). I have seen several instances of wrong information being stored in this memory which will render it useless even though it should work.

ref:
http://forum.thinkpads.com/viewtopic.php?t=27864
http://forum.thinkpads.com/viewtopic.php?t=34684

I believe that for the 600X systems, the memory timing is setup for CL3. Which means that PC100 and PC133 modules can be used as long as they meet a second requirement: refresh cycles. This is where the "low" and "high" density description enters the picture. A "low density" module requires 4096 (4K) refresh cycles in a specific amount of time. "High density" modules require 8192 (8K) refresh cycles in the same amount of time.

As long as each individual memory chip on the module is 16MB (or smaller), then that would make the module "low density". Since you need 16 16MB devices to add up to 256MB that's the usual way you can identify such modules. If there are only 8 chips on the board, then that means they are each 32MB and I'm not aware of any memory manufacturer that designed those parts with 4K refresh. If Crucial (Micron) guarantees those modules in your 600X and will fully refund your money (return shipping included), then you have nothing to lose.

rkawakami wrote:I believe that the Infineon module HYS64V32220GBDL is a high density version. The first "32" refers to 32MB devices which will require 8K refresh cycles. The datasheet is available from here:

HYS64V32220GDL datasheet

I haven't been able to access that datasheet but note that the part number does not quite match. There is a missing 'B' near the end. Searching Google groups archives I found a post that indicated the 'B' part is low density. There is also this Ebay auction: item 120147636922.

Since Infineon spun off the memory group it is very hard to locate data on the older modules. Most vendors have a page telling how to decode their part numbers but I can't find one for the module in question.

I have a feeling that the "B" designation only pertains to the package type of the individual ICs on the module. In this case, "B" = BGA (ball grid array) parts, but I'm still looking...

edit: Haven't turned up anything on the meaning of the "B" designation except the same post you referred to from Google Groups. I guess maybe I'll buy one off of eBay and see...

BTW, I work for a company that used to have a DRAM joint venture with Infineon. When they pulled out that compnay eventually absorbed us as a subsidiary. Sort of like the child owning the parent. I would have thought that we would have some Infineon databooks around here but I can't find any! They must have been burned .

edit2: Finally found it! Go to this datasheet site:

http://www.datasheetarchive.com/

and plug in "Memory Spectrum" in the search field and select "Description Search" as the search type. That should bring up a list of 4730 hits. Click on any one of the icons in the "Information" column. That will download an Infineon .PDF file. On page 18 is the part numbering system for SDR SODIMMs. "GBD" means 144-pin SODIMM (FBGA-based). In other words, "fine, ball-grid array", the package style being used by each memory IC.

It's possible that the "Designator" or "Part Number Extension" fields can define any difference between built with "low" or "high" density components.

@rkawakami

Robbyrobot: I see a lot of misinformation on this subject in the German Thinkpad forum, and particularly at the German Ebay site... people claiming that only 16-chip PC100 modules work in a 600X, which is nonsense.

I see you didn't comment my remark, and am curious if you disagree. My admittedly limited experience is that PC100 modules will work in a 600X, period. Some have 16 chips, some have 8. I have an Infinion 256MB module with presumably 8 chips (based on the size, but impossible to tell exactly since it was made during the shortage of ceramic housings for the chips and thus is covered with an epoxy coating) that works just fine in my 600X.

I wasn't entirely clear on exactly what you meant... that only PC100 works in a 600X or only 16 chip 256MB modules do.

Taking each one separately, yes you can run PC133 modules in a 600X. I think that I have some Micron PC133 units in a couple of them.

As far as the 16-chip 256MB module is concerned, I believe that that's the only type of 256MB module that you can run in a 600X. This is based upon what I know of the refresh characteristics of these "low density" modules vs. the "high density" versions. My understanding is that the 16M chips on the "low density" modules have the proper refreshing spec (4K cycles every 64uS) which matches what the 600X memory system requires/generates. The 32M chips on the "high density" module require 8K cycles (at least the ones that I am familiar with). This is usually what causes those memory modules to either fail POST or be detected by Windows as half the size.

The epoxy coating you are referring to is typically called "COB", chip-on-board. It is a packaging technique which places the silicon die directly onto the printed circuit board and then covers it with a mound of plastic (resin). This process can be used as a low-cost method of assembly. It also has been used to make the part more "secure" from tampering or copying.

Do you have a part number for that Infineon module?

I wasn't entirely clear on exactly what you meant... that only PC100 works in a 600X or only 16 chip 256MB modules do.

Actually neither
I'm well aware that some PC133 modules (at least those from Crucial and if I've understood correctly the so-called "low density" - 8-chip per side - modules) work in a 600x, and I have no reason to believe that any 100MHz 256MB module should not work, since the computer has a frontside bus speed of 100MHz. However, I'm uncertain whether 4-chip per side, 100MHz, 256MB modules even exist.

In Germany, people are selling 8-chip per side 100MHz 256MB modules as if they were something special. I'm not at all sure they are: my understanding is that only 133MHz 256MB modules of this type are, and are compatible with 100MHz frontside bus systems like the TP600x.

The epoxy coating you are referring to is typically called "COB", chip-on-board. It is a packaging technique which places the silicon die directly onto the printed circuit board and then covers it with a mound of plastic (resin). This process can be used as a low-cost method of assembly. It also has been used to make the part more "secure" from tampering or copying.

Here in Germany, we only saw such RAM modules for a short time in the mid-90s, when there was a shortage of ceramic chip housings. Such modules are nowadays considered "inferior", but that's just a subjective judgement and is not borne out by testing (for example with memtest86+).

Do you have a part number for that Infineon module?

HYS64V32220GBDL-8-C2, 32Mx64 SDRAM, C6S14708005, PC100-222-620 (256MB, Sync, 100MHz, CL2). Incidently, the PC100-222-620 designation is identical to what is printed on an 8-chip per side 100MHz 256MB module I have, so I suppose it's possible that there are 8 chips per side, but it's impossible to tell just by looking.

However, I'm uncertain whether 4-chip per side, 100MHz, 256MB modules even exist..

They do, the one 256mb sodimm I've got in my 600x is a 100mhz 4-chip per side module.

hseaver wrote:

However, I'm uncertain whether 4-chip per side, 100MHz, 256MB modules even exist..

They do, the one 256mb sodimm I've got in my 600x is a 100mhz 4-chip per side module.

Whoops, sorry, I was mistaken on that, I was looking at the 128mb module.

@hseaver: Check your Inbox!

On a related note ...

I'm looking for 256MB for a Thinkpad 770Z with a 650 MHZ PIII.
I've found this Kingston PC133 module KVR133X64SC3/256 which is only 1/3 the price of the equivalent PC100 module. The datsheet is here
http://www.valueram.com/datasheets/KVR133X64SC3_256.pdf

Now the interesting thing is that normally I would not expect this module to work as it is configured as 8 chips 16Mx16bits. However they are specified as 4K refresh - so my guess is they might. The deal I have been offered means I cannot return them if they do not work

Do you think they will work e.g. would they work in a 600X (which has a similar spec to my "new" 770Z)?

I just bought a set of Crucial's 256MB PC133 SO-DIMMs off eBay for a T22, and they work great. I got the set for what it cost for single new one.

If anyone is interested here are the part numbers off them:
Crucial part #CT32M64S4W7E.16FG
Micron part #MT16LSDF3264HY-13EG4
Datasheet

Crucial also lowered the price a few dollars (at the time I wrote this), so now they're only $36.99 each.

Forgot to put this in my eBay to-do list:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0145824597

Some eBay newbie who understands sniping got a low-density 256MB PC100 Crucial module for $18.16 (shipped US). Oh, and two 128MB PC100 modules for free.

i bought a 256 PC100 off craigslist for 15$ just a few hours ago, it's low density chips. i would look there, i see them here atleast once a week. allthough not exactly as cheap.

So, can I assume that any PC100 256mb memory will work in a 600x? I know that with PC133 256mb you need low density, i.e. 16 chips rather that 8 chips. I'm still a little unclear about PC100.

I would say that many PC100 256MB modules would be of the low density type, but not all. As long as you see 16 ICs on a 256MB module (8 for a 128MB), then that's low density, regardless of which speed rating it is (PC100 vs. PC133).

Okay, through the kindness of BillP who has allowed me to borrow his Infineon 256MB module, here's what I found:

http://www.kawakami-ca.com/billp_module/

The short version: Using a bench-top memory tester, it's a low-density compatible module (4K refresh). When I first found that Infineon document (see my Aug 03 post), I glanced at the part numbering system and it seemed like the "32" in the part number meant 32M devices or "high" density. Looking at the table on page 20, the "component organization" is 16M x 16. The 16M being "low" density and the "x 16" a part which has 16 output pins. If true, this would mean that there ARE only 8 devices on the module AND it is low density.

Wow, there is some awesome information in this thread ... Thanks for the update Ray.

Update: Bought an identical Infineon module for $30 yesterday:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0168679366

I'm going to take the heat shield off and see what's underneath!! Pics to follow in a couple of days...

PC100 sticks are getting cheaper. I just bought 4 of them for $30 each on E-bay. If you are patient, you can find them cheap:

He had 15 sticks: E-bay # 200159851636