Aaden: Is that a typo or does your CPU actually have a clock of 1.6 GHz?
If so, I'd say that's the bottleneck and lowering the resolution won't do any good.
andre0799: My CPU had 1.6Ghz with Turbo boost up to 2.8 Ghz
Ps:i7 has 8 cores (4 physical)
It's 4 cores, able to work on 8 parallel threads - which doesn't affect (most) games.
The Turbo mode overclocks a single core by two "speed bins" to 2.8 GHz or two cores by one "speed bin" to (I'd guess) 2.2 GHz, or uses all four cores with 1.6 GHz, depending on how many threads an application uses. Since TW2 is (from what I heard) four-core-optimized, you most likely are stuck with a 1.6-GHz-Quadcore, which, I think, is too slow for TW2.