I am tryign to upgrade my ASUS K50IN with Core2duo t5870. According to the info i've found it is possible go up to T9600, but can you do me afavior and double check me. I am a little bit confused, becouse my original t5870 is ppga479 and 800mhz, while t9600 is pga479 with 1000mhz,both are Socket P (478) (theoreticaly my chipset can support 1000mhz) ..here is what I have:
According to the Asus site you K50IN doesn't have a t5870 https/www.asus.com/Laptops/K50IN/specifications/. I would say if its cheap to get buy the CPU and update the BIOS to the latest version you can if possible.
It isn't enough for the two CPUs to have the same socket and FSB. The BIOS has to support the new CPU. Each CPU has its own quirks (unique features and bugs), and the BIOS has to know how to handle them for the CPU to work. The better motherboard / laptop manufacturers will list in each BIOS revision's readme.txt exactly which new CPUs are supported with that BIOS revision. You'll have to dig through those to find out if the new CPU is supported. (If the price is low enough, it may be easier just to buy it and try it, rather than research it.)
Also be aware that some of those CPU models were released in both soldered and socketed versions. The soldered versions were OEM so used the same model numbers. So until you crack open the laptop, you won't know for sure. Though the fact that Asus offered the laptop with a choice of CPUs is a good sign that it's socketed.
The different FSB may be a problem. Desktop motherboards can usually have their FSB changed. Laptops not so much. So if your old CPU uses a 800 MHz FSB, that may be all it's capable of.