IF you're budget is $400 and you need more CPU power, wait and save more money. Almost all laptops under $400 have Celeron and Pentium low-power CPUs that won't be as powerful as your current model. Unless the laptop is broken, it's a pointless upgrade. There are a couple of laptops out there with the i5 4200M processors, they are around $500-$600. They will be a noticeable upgrade