should be on a sticker on the bottom of the laptop. Most of the major memory makers have utilities on their websites to show which parts are compatible. Here's Kingston's for example.

System memory standard : 8,192 (4,096 + 4,096) MB
maximum expandability : 16,384 MB
technology : DDR3 RAM (1,333 MHz)

http://www.toshiba.co.uk/discontinued-products/satellite-c55d-a-15h/

Does the "15h" make a major difference, or do you suppose that the different flavors of C55D-A use the same type of RAM?


Thanks!

http://support.toshiba.com/contact

You don't want to buy the wrong memory by accident, I've done that.

I'm hopeful that the label will give me that last piece of the puzzle, but I'll keep your link in mind.

https://www.crucial.com/

...and use the Crucial Advisor tool about halfway down the main page...

You need to know the manufacturer (Toshiba), the product line (Satellite C55D), and the model (ex. C55D-Axxxx)... you can find the actual model number somewhere on the laptop, usually by the serial number.

Input the information, and the tool will give you information on the exact RAM that you need including maximum RAM capable, pricing and availability.

Good Luck...!!

It will also check for maximum the system allows. You should make sure the system can handle more memory. It should be able to but some of the cheaper laptops are quite limited.

Pretty sure that this one can handle 8 at least, which would be more than adequate for my son's needs.

Thanks.