T21 memory - Low or High Density, CL2 or CL3

[iann070]

I would like to upgrade my ThinkPad T21 memory to 512MB.
At the moment it has one stick of 128MB (PC100 - CL3) so would need to purchase two sticks of 256MB to max it out to it's 512MB limit.

On searching the net I understand that the ThinkPad T21 will only work with Low Density PC100 memory, so a 256MB stick would have 16 chips (8 per side) rather than High Density which would have 8 chips (4 per side) ???

The other thing that is concerning me is the CL rating.
I understand that this is the clock latency, and CL2 is faster than CL3, and that some systems can use one or the other, some can use both.
The current memory stick in my ThinkPad T21 is CL3, but the memory I've seen on eBay is rated at CL2, so I'm not sure if my ThinkPad will work with CL2, and if you can mix CL2 and CL3.
I've read that the ThinkPad's are a bit fussy when it comes to the type of memory so I just want to get some advice first.

Cheers
Ian

[Bgradid]

CL2.5 will work just as well as CL3, it'll just clock itself to whatever one it needs.
And yes, you need low density ram, it's also best to stick to PC100 from what I hear

My laptop came with a piece of ram that isn't 'officially' compatible, but, works great. Here's the serial number to extend your searches
KTD-INSP7500/256

[JHEM]

Welcome to the Forum.

Search eBay for 33L3070, the part number for the IBM memory you need for your T21.

Shouldn't run you more than ~$45.

Don't worry about the latency, it's not an issue.

Regards,

James

[TonyJZX]

read this:

http://forum.thinkpads.com/viewtopic.php?t=22325

I suspect that by 2004, IBM had tweaked the hell out of the mem ctrl to make it more compatible...