T21 with PC133 RAM

[maci]

Hi!

What do you think, can a T21 work with 2x256MB PC133 RAM? Because I've read that only T23 fully compatible with PC133, but some people said that their T21 works with PC133 and they said, that kingston is a better choice, because it has more chance to work with.

What do you think?

[rkawakami]

Welcome to thinkpads.com!

Some PC133 modules can be used in the T21, which uses a 100Mhz bus (i.e. PC100). The two things to watch out for and which should give you a better chance of working are:

1) Use low-density modules. See this thread for more information about low-density memory.
2) Try and use modules that have a CAS latency (CL) rating of 2 instead of 3. Those modules may cost a little bit more, but they are faster. A PC133 CL3 module can actually be slightly slower than a PC100 CL2 module.

The manufacturer of the module does not really matter too much. If they have done their job correctly, it would have been tested to an industry-standard timing specification. However, you will be better off staying with "name-brand" memory (the actual components on the module, not the module maker) from the likes of Samsung, Micron/Crucial, Elpida, Mosel Vitelic/ProMOS (full disclosure: I work for MV which in turn is owned by ProMOS), Hyundai/Hynix, Infineon, etc. Basically, any company whose main business is in DRAM production. Those manufacturers do not always make their own modules but from my viewpoint (a memory test engineer), I would prefer to have them being used than some "no-name" or re-marked memories.