IBM ThinkPad T40 2GB Max RAM

Maximum memory for this model is 512mb, no cpu upgrade neccessary. 2 x 256mb sticks is OK.

Here is a link to the Crucial website where you can order memory modules for your computer.

Hi - according to memory suppliers your T23 has the following memory capacity / requirements:

• IBM ThinkPad T23 maximum RAM capacity: 1GB
• Your IBM has Two (2) memory slots or sockets
• Module upgrade PIN count is: 144-PIN
• The memory speed is: SDRAM 133MHz, PC133
• The laptop DIMM type for the ThinkPad T23 is: SODIMM, SO-DIMM, Small Outline DIMM
• Non ECC

If you are meeting these requirements, you may have a defective module.

Also, according to Lenovo's page on the machine:

Memory
The system has 128MB or 256MB of memory standard and can be configured for up to 1GB of addressable memory. Memory options up to 512MB SDRAM SO DIMMs each can be added in the two available slots for memory expansion. The standard 128MB of memory is expandable up to 640MB and the 256MB of memory is expandable up to 768 MB of addressable memory with 64, 128, 256, or 512MB SO DIMMs without removing the 128MB SO DIMM that is standard in one of the internal slots for memory. For customers that need the maximum 1GB to which memory can be expanded, it is necessary to replace the 128MB or 256MB card with a 512MB card plus add another 512MB card in the extra slot. Only 133MHz DIMM memory can be used in this system. The use of 100MHz DIMM memory is not supported in the T23 systems.

This means yo can trouble shoot the 512MB modules individually by installing one of the original 128MB modules and one of the new 512MB modules (for a total system memory of 640MB). If it does not boot, try again with the other 512MB module. This will help you identify a defective module that may be preventing the machine from booting.

I hope this helps & good luck!

Well, what a mine field!
I found this;
There are at least 9 different R40 Thinkpad models. Look for a label underneath & see if there's a "Type" number...something like 2681, 2682, etc. Once you find the number, go to the following site & select your model/type from the dropdown menu:
http://www.crucial.com/store/listmodel.asp?cat=RAM&mfr=IBM&productline=ThinkPad&submit=Go

And being a 256Mb standard, that may be all it can handle. The above link is rather old but worth a try.
Hope this helps.

The Thinkpad is installed with 128 MB SDRAM is standard, and is expandable to 512 MB
There are two memory slots, to expand it to 512 Mb you need two 256 Mb RAM modules and throw away the 128 Mb RAM module, but if you don't throw away this module and you insert a 256 Mb RAM module in the 2nd memory slot then your total memory would be 384 Mb.

The T42 can support up to 2 Gb of RAM.
The laptop comes with 512Mb of RAM under the keyboard and a spare memory slot on the bottom of the laptop.
To install 2Gb of RAM put 1Gb in the memory slot under the kerboard - need to remove the old RAM and put the other 1Gb in the memory on the bottom of the laptop

T42 Memory specs.

• 64-bit Double Data Rate (DDR) non-parity SDRAM memory
• PC2700 at 333MHz
• Two 200 pin SO-DIMM memory slots, one slot is pre-populated with 256MB or 512MB, leaving one socket available
• Supports up to two 1GB SDRAM SO DIMMs
• Supports maximum memory up to 2GB

noway max is max. buy yourself a 1gb and don't try to beat the system or lose it.

Max CPU for IBM T20, 21, 22 is Pentium III FCPGA2 1000MHz (1GHz). Max memory is 512MB (2 x 256MB PC100/100MHz). Max hard disc is 250GB ATA. Newest BIOS is from April 2004 at the homepage Lenovo.

1) Not sure what you want to do. Return to Win98? You may be hardpressed to find Win98 drivers, especially if you have any newer peripherals.

2) Since a cpu has no mechanical parts, it makes no difference whether it is vertical or horizontal. A cd/dvd drive however may be a different story.

3) If you only have 2 RAM slots that hold a max of 256mb, it stands to reason that you can only have 512mb total. There used to be some software programs that were supposed to have the effect of increasing RAM, but I never had much faith in them.

To upgrade your CD drive there is a screw on the bottom of the machine that holds it in place. Remove this screw and the drive will slide out. I buy most drives for my customers and shop from Ebay. I've found that there are some very good vendors with good prices and warranties there. Now for the memory. The memory you need for your machine is PC2100, and 1g is the max. I mainly use Kingston or Infiniton. Both of these are good chips, and there are other good chips out there. I suggest that you use two 512mb chips that are the same make. I've found that sometimes two different chips will create a conflict with each other. The memory is located under a panel on the bottom of the machine. For memory I use pricewatch.com If you have any other questions please fell free to ask.