It would help to have some links to the systems youre looking at.
If you will ocassionaly play games i would suggest to go with the i3 and dedicated 1gb gpu because the HD4000 in the ivys are horrible for gaming especially at 1080p.
Anyone with some IT common sense should know that integrated graphics and playing games at 1080p resolution do not go well together.
I suppose I would choose the i3 + dedicated graphics card if you are going to play games sometimes. But it really depends on which graphic card you are talking about. The nVidia GT 610m is a dedicated graphics card, but benchmarks have shown that the Intel HD 4000 actually performs better.