First time buyer seeking advice on these two systems. Going the refurb rout would the first gen quad core i5 or the second gen dual core i5 be better? Are there any charts rating performance? How about the graphics? The 4850 was the best card in the first gen. The 5670 is the slower of the two in the new model. Does the 5670 beat out the 4850? Any input is appreciated. Thanks in advance!