Minimum computer specs for multitabling cash games?

I currently have a laptop that i 8 table on, and because its only a 14' screen it wont allow me to do any more. so i am planning on buying a large monitor but i was wondering what specs would be needed on a pc to multi table smoothly??? Im not ready yet but i plan to 24 table one day so want a pc ready for that. thanks

Do you need a nice monitor with 21' at least

For smooth multitabling you need one big enough monitor or you could always use 2-3 smaller ones with a good/average graphic card and depending on the number of tables you will need a good amount of RAM if you are planing to do something else beside poker