Hi,
I have the same n5110 but with slowpoke i3-2310M. And I've successfully replaced my slow CPU to i7-2640M. It works perfect and even with 65W charger. If you want some faster quadcore like i7-2670QM 2.2GHz or i7-2630QM 2.0GHz in this case probably 90W or even 120W charger will be needed. And don't forget about new thermal paste for replacement.