There are really just two types of boards -- integrated or discrete video.  And while one will fit  in place of the other, the heatsink assembly required is different.  Also, integrated video boards will run fine on a 65W power supply -- discrete needs 90W or 130W.  
Greetings, Is there any way to determine the Motherboard number on my non working Studio 1558 without actually opening the computer up? Thanks in advance for all info.   . TOS76>   
Motherboard number