I'd like to add more RAM to my Ubuntu installation ( running on a Dell Inspiron 640m ). Is there any inbuilt command or package to find out the current RAM chip specifications (manufacturer, type, speed etc) from within Linux ?
This might help: Linux: Check Ram Speed and Type.
Alternatively, if you can boot from a windows system, the Crucial System Scanner tool will give very good details on what is installed and what can be upgraded on the system (along with a shopping cart too). It will need an Internet connection.
Here is a quick reference from Crucial:
I am assuming, you do not want to open the system and look at the memory sticks.
As an alternative approach, since your machine is from a major manufacturer, you can use an online tool such as Kingston's memory search to lookup the memory type from the model number.