Apart from the processor, it is essential to select the proper upgraded processor as per your budget. You must have to consult the system engineer to get the suitable version of the processor to replace the processor. In the earlier years the Celeron mother boards are install in most of the system and in laptop or notebook the Celeron grade motherboard get install.
In the present era, Pentium grade and new version of processor are available with higher capacity of the processing the database. Similarly you must have to upgrade the BIOS as per your configurations.
If you install the faster processor than it carry more power load so if you install old version of motherboard than it does not work it is better to select the proper motherboard that suits to your requirement.
The motherboard is available around $100 pr more. You must have to select the proper version of the processor based on the motherboard. If you want to install to select the motherboard you must have to get the details about the capacity of the motherboard that suits to your needs.
It is better to select the motherboard that suits to your existing needs.