I think that the i7 has hyper-threading so for some apps might make use of the 4 effective threads. The i7 also has a larger cache but then it is considerably

I think that the i7 has hyper-threading so for some apps might make use of the 4 effective threads. The i7 also has a larger cache but then it is considerably slower. You would need to find some actual system benchmarks to make a meaningful performance comparison if that is one of your criteria. Personally I would go for the 3.3GHz i5. In my evaluation it is a more modern system and thus would be upgradeable for a longer period.