How much of a DIFFERENCE will it make in terms of running Rohan for the following specifics?:

Processor: Intel Core i7-2670QM
Operating System: Windows 7 Home Premium 64-bit
RAM/DDR3: 4GB
Hard drive: 640GB, 5400 RPM
Graphics card: NVIDIA GeForce GT 540M
vs.
Processor: Intel Core i7-2670QM
Operating System: Windows 7 Home Premium 64-bit
RAM/DDR3: 6GB
Hard drive: 750GB, 5400 RPM
Graphics card: NVIDIA GeForce GT 540M

The only difference is the RAM and hard drive, will they make any difference in terms of running game? If so, how much of a difference? Also, I'm probably going to end up getting the laptop with the first set of specifics, so will Rohan run well on that system? Thank you in advance! ;D