Can I upgrade from a T4500 to a T9800

Solution
A somewhat high probability:
http://ark.intel.com/compare/37005,42925
What you need to do is run a diag program like speccy or Everest and get the exact chipset (945GL, 945GM, etc), then look up that chipset on http://ark.intel.com and look at compatible products.
I think the only thing that will prevent the upgrade is:
A. BIOS limitations
B. the 9800 is 1066MHz FSB and your 4500 is an 800MHz FSB.

Get the exact chipset and post a pic it if you get lost comparing CPUs and chipsets on ark, I've done lots of CPU upgrades in laptops, more than happy to help.
A somewhat high probability:
http://ark.intel.com/compare/37005,42925
What you need to do is run a diag program like speccy or Everest and get the exact chipset (945GL, 945GM, etc), then look up that chipset on http://ark.intel.com and look at compatible products.
I think the only thing that will prevent the upgrade is:
A. BIOS limitations
B. the 9800 is 1066MHz FSB and your 4500 is an 800MHz FSB.

Get the exact chipset and post a pic it if you get lost comparing CPUs and chipsets on ark, I've done lots of CPU upgrades in laptops, more than happy to help.
 
Solution
You can't 'find' the BIOS limits. You have to google other people having success with your model, or take a shot in the dark. And bus speed is how fast data moves, for lack of a better term. If you go up to a 1066 FSB, all your hardware now has to speed up to meet the demand of the CPU, causing importantly in a laptop, more heat that it may not be able to dissipate. Your RAM may not be able to ramp up higher without problems, causing a decrease in RAM life also.

http://en.wikipedia.org/wiki/Front-side_bus
 




I upgraded the same Asus K50IJ from T4500 to T9500, which has the same FSB @ 800MHz and it works perfectly😉
I don't think T9800 will be suitable.