Core i3 will be slower man, I'm telling you. i7 will always be better than i3 unless the i7 is ten years old. xD
False, the i7 620m is a generation behind the new i3, and is a dual core at 2.6Ghz.
The i3-2120 is a dual core at 3.3Ghz, so right there it is already faster.
Sandy bridge is also about 20% faster clock for clock than the previous architecture, so the desktop i3-2120 should be quite a bit faster.