Picture Mounting Card I've Got A 3 Yo Toshiba Laptop (M40), Which Limits Do I Have, Regarding An Upgrade Of The Graphic Card?

I've got a 3 yo toshiba laptop (M40), which limits do I have, regarding an upgrade of the graphic card? - picture mounting card

The original video card is an ATI X300 does its job (you can Team Fortress 2, playing in the example), but when I update, I'm thinking of some compatibility problems?
Within the last 3 years:
SATA EIDE found
AGP was sent to the dust PCI-E
He went from DDR to DDR3 Ram

A standard for mobile video cards has changed?
Can a Nvidia Mobile 8600, when I wanted it? The score seems quite the same:

Links should be granted only examples of the 2 cards and the contents should be taken in the linked sites.

My X300 - here in the picture at random by an eBay user.
http://cgi.ebay.de/MXM-Grafikkarte-ATI-M ...
A new mobile Nvidia 8600th
http://www.directron.com/90c1ciz5jxbn0.h ...