The new system should give you a lot more CPU poke, as the old one is only dual core 4 thread. You get double the physical cores in the new one, and they're a newer generation too.
As for hard disk, the performance option would be to go for an internal SSD and USB connected bulk storage drive. However, purely for raw processing, hard disk performance isn't the limiting factor so you're not likely to notice a difference due to that. If you want an in-between solution, Seagate do some hard disks which include a built in flash cache which operates transparently, potentially giving you a boost in some areas to SSD like performance while retaining a large capacity.