Which memory have you in your Thinkpad T21 ?

[ludox]

To see if exist differents modules that are Ok for Thinkpad T21.

I propose to people to post here The reference and manufacturer of the memory module the have in their T21 :

Except for IBM references. And if certains have différents modules available, thay could test it and post here results after hours of use.

Cause, I don't find more infos on the web.

It is your turn :

[rkawakami]

All modules that are low-density "PC100 CL3" or "PC100 CL2" should be able to work in the T21. I have used Micron/Crucial, Hynix (Hyundai), Mitsubishi, Mosel Vitelic/ProMOS (full disclosure: I'm an employee), Kingston, Samsung, Elpida and others.

The big question is, "How do you determine what is low-density?". This is easily done with some math:

- if it's a 64MB module, four (4) memory chips should be on the board
- if it's a 128MB module, eight (8 ) memory chips should be on the board
- if it's a 256MB module, sixteen (16) memory chips should be on the board

If there are LESS than that, you have a "high-density" module and it will not work in the T21.

This all assumes that there is NOTHING wrong with the module itself. That is to say, there are no bad storage locations (bits) and that the SPD (serial presence detect) information is correct. Both of those things can render a module useless.

Your best bet is to use memory diagnostic software to test the module. As long as the computer can boot, you can run memtest86+ and it will determine if there are any problems.

[ludox]

Interesting cause low density was not clear before.

So, Double sided module are low density ?



But pc133 modules would works also, no ?
If it exist in low density.

[RealBlackStuff]

Read this: 'PC100 that is actually PC133' just below your own post.

[rkawakami]

So, Double sided module are low density ?

Generally, yes for 128MB and 256MB modules. It's hard to put 8 or 16 parts on one side of the module . Being double-sided does NOT automatically equal "low-density".

But pc133 modules would works also, no ? If it exist in low density.

Yes, PC133 can also be used as long as you are using "low-density" modules. I also believe that the T21 system requires modules that are CL3. By definition, if the module works as designed at CL2 (and is marked as such), then you can also use it as CL3. However I have seen several modules which have not had the proper SPD information programmed into them and which caused them to not work as they should.

(ref: http://forum.thinkpads.com/viewtopic.ph ... 094#201094)
(ref: http://forum.thinkpads.com/viewtopic.ph ... 151#232151)

[ludox]

So if I choose Kingston, the T21 ref cost 100€.

But what do you think about this ?

http://www.valueram.com/datasheets/KVR1 ... 3L_256.pdf

I understand 16 chips and CL3. I must buy to try...



And this :

http://www.valueram.com/datasheets/KVR133X64SC3_256.pdf

only 8 chips so don't seem good.

[Sloba]

Four years ago I was searching for memory for T21. I have tried 9 different modules and 8 gave me "unreliable memory detected".
However, #9 was perfect and that one was Centon PC133/100.
Everything works perfect since day one.

www.centon.com

[nikki605]

Just to add my 2 cents worth - I was looking to upgrade the single stick, 128MB memory in my T21 back in 2004. I had just suffered a HDD failure and decided to upgrade to Win XP Pro when I installed the new drive. I knew I would need more memory, so I bought a couple of 256MB "Genuine IBM" memory sticks off eBay. I just about die now when I look at what I paid for them

They were listed as IBM FRU: 33L3070, as others have mentioned in this thread. They arrived sealed (new) in IBM antistatic bags. When I opened them, I found IBM labels on one side and Micron labels on the other side, of each stick.

Click here to see a photo showing both labels. You'll also see 8 memory chips on each side of the module.

The IBM label says PC100 CL3, while the Micron label says 133MHz CL3. So as Ray said, you can run memory designed to operate at 133MHz, "under-clocked" at 100MHz. In any event, they have worked flawlessly since I first installed them in 2004. Earlier this month I had to replace the motherboard for another problem and just moved these 2 memory sticks into the replacement mobo. They continue to work without error.

I went to the Crucial (Micron) web site this morning and ran their System Scanner to see what it would detect and recommend for memory. This is what it displayed for a 256MB module:

256MB, 144-pin SODIMM, SDRAM, PC133 memory module
CT484656

US $58.99

Module Size: 256MB
Package: 144-pin SODIMM
Feature: SDRAM, PC133
Specs: SDRAM, PC133 • CL=2 • Non-parity • 133MHz • 3.3V • 32Meg x 64

Their price of $58.99 is about half what I paid in 2004. I was stubborn... I had to have "Genuine IBM" and I paid for it

p.s. - And BTW, CPU-Z does not display any SPD info on my T21!

[tfflivemb2]

For the record, here are the two sticks that are in my T21:

Crucial
PC133S-222-540
BZABF53002
200205
256MB, Synch, 133MHz, CL2

[ludox]

All of this is interesting cause I will try the kingston ref cost less than 30 €.

But recomended by your test is CL2 and the kingston like the Micron is CL3.

Like for PC100, some good quality pc100 can pass pc133, some cl3 must pass CL2 and the micron was perhaps capable.

I hope that the kingston cl3 will pass on my T21.

So I could buy another to pass to 512Mo.