I have been running a i5-2500k for the last 2 years and it has been a great processor. However recently the motherboard (MSI Z68S-G43) has starting whining and acting odd with disconnecting drives. I was going to replace it with an Asrock Extreme4 Z77 motherboard and still might but I thought, would it be worth while upgrading to haswell (i5-4690k) instead of replacing an old motherboard?. What performance increase would there be if any? Is it worth spending the ~£260 instead of £90 for a new old Z77 motherboard?