Help with X21 And RAM (high/low density issue?)

[UnixNut]

Hello all

I am upgrading a friends X21 Thinkpad (from 192mb to 320mb) by replacing the 128mb sodimm with a 256mb sodimm.

The problem I have come across is that it refuses to detect the memory (It is IBM certified infineon memory).

If I put the 256mb stick in and boot, the laptop reads 192mb (i.e. it sees it as a 128mb stick).

I have tried this with different 256mb sticks, and all of them are detected as 128mb.

Only one stick is not, and the only difference I can see is this stick has 16 chips on it, while the others have 8.

Reading on this forum, I have come across references to "high density" and "low density" RAM.

I presume that the 16 chip 256 mb stick is low density, while the purchased one is high-density (8 chips).

Issue is. I cannot find many low-density chips for sale, and those that are for sale are more expensive then their high-density counterparts.

I have never come across this before, so could someone explain to me what exactly is the problem? (providing background info in this is nice as well).

More importantly, is there any way of getting the X21 to take high-density RAM? as low-density ram is getting scarce is it possible to get high-density RAM working on the laptop?

thanks!

Edit:

Also reading about, it seems that the X22/3/4's are known to take hi-density RAM, is it possible to replace the X21 motherboard use a X22, X23 or X24 motherboard (if all else fails)? How compatible are they (e.g. size/shape/layout) to the X21

[JHEM]

This will work in the X21.

$46.99 from Crucial.

Regards,

James

[bri]

You need low-density. I shopped a couple days on eBay, seems like the going price is $45 shipped, most auctions end around there and there are a bunch of buy-it-now at that price. Might as well buy-it-now since you won't be able to win a bid at less. I got one from this seller at slightly lower than the going price:

http://stores.ebay.com/XReplay-Online

His current listing shows a low-density in the picture but doesn't specify in the listing. Ask him for sure. The one I got specified "32Mx64" in the listing which I think is the chip count and also he verified it for me when I asked.