Thinkpad T42 memory upgrade

I have a T42 and I want to upgrade its memory. It currently has one 512 MB PC2700 (DDR333) memory module. If I add another memory module to the empty bank, can it be PC2100 (DDR266) or PC3200 (DDR400) or does it have to be PC2700? Is it okay if I add 1 GB or 256 MB module to the empty slot? Or should it be 512 MB like the one I have already installed?

 

The T42 does not support dual channel memory so there is no benefit to be gained by using the same size memory modules. The important thing is to get more memory. Unless there is a significant cost advantage, I'd get PC2700 or PC3200. The PC3200 will run at PC2700 speed.

 

So does any 200-pin DDR SO-DIMM module work in T42? Does it matter how many chips there are on the module (16x32, 8x64 etc...)

 

Yes technically, but u dont want to buy slower memory than u already have because then u wont get ur full potential out of ur laptop. If u get a pc2100 stick and put it in there, then ur other pc2700 will downclock itself to match the 2100's speed. That wouldnt make a whole lotta difference, but its not any more expensive to get the proper pc2700 speed so do that at the least nothin slower.

 

Are you sure about this? I installed 1 gig PC3200 module and the laptop won't boot with the module installed.

 

You can not use the PC2100 nor PC3200, because T42 only use the PC2700.
Standard memory of T42s:
. 128-MB DDR SDRAM SO-DIMM (PC2700) card × 1
. 256-MB DDR SDRAM SO-DIMM (PC2700) card × 1
. 512-MB DDR SDRAM SO-DIMM (PC2700) card × 1
. 1-GB DDR SDRAM SO-DIMM (PC2700) card × 1
---> Option memory of T42s:
. 128-MB DDR SDRAM SO-DIMM (PC2700) card × 1
. 256-MB DDR SDRAM SO-DIMM (PC2700) card × 1
. 512-MB DDR SDRAM SO-DIMM (PC2700) card × 1
. 1-GB DDR SDRAM SO-DIMM (PC2700) card × 1
(maximum of 2048 MB)

 

I have seen it work though when going outside the spec there is a higher failure rate.