Are the Motherboard from the i5-520m and the i5-720m the same?

I want to change the processor from the i5-520m to a faster one.

The Intel website claims the supported sockets from the i5 processor are "PGA988" and "BGA1288". The supported socket from the i7-720qm for example is "PGA988". The Laptop was shiped with the i5-520m and i7-720qm aswell others. My question now is, did they use the same motherboard (PGA988) or a different (BGA1288).

I could not find any information on the used socket. Did anybody do this processor swap?

Thanks