im certainly going to say the 3770 ,as it is proven to be a very good processor for DAW but know doubt someone will suggest going for something newer . The 3770 does not over clock anyway and to be quite honest unless your going to be using 800 tracks of vsti’s ( bit over exaggerated ) you will not be anywhere near the limit on this baby , there are very good for the buck
Pointless getting an i5 3570 unless you are willing to overclock, they are designed for overclocking, saying that, if overclocked correctly with a good motherboard they can outperform i7 easily.
I’d recommend Xeon.
Have a look at the specifications of the HP series Steinberg suggests as ideal hardware for Cubase and make your decisions based on that as a model. Cubase: Music Production Software | Steinberg (near bottom of page)Made for each other: Cubase and HP
Finest software requires finest hardware. That’s why our best software specialists rely on the world’s leading PC hardware manufacturer. Cubase 7 is quality-tested with HP’s professional Z series workstation computers, ensuring highest performance and maximum reliability packed in a rock-solid chassis. Carefully selected components optimized for recording, editing and mixing allow for efficient audio data transfer rates throughout the whole system. Be it the industry-proven Intel XEON processors or the ultra-fast SSD drives, HP Z machines squeeze the best out of Cubase, speeding up your entire studio software environment.
With the E5-2687W Xeon being the top dog! But look at the price (double that for two), though if you NEED the capacity, it becomes a matter of scheduling the outlay.
Here are good benchmarks PassMark - Intel Xeon E3-1230 @ 3.20GHz - Price performance comparison
comparing all but newest cpu
Good luck and let us know what you do, remember that the technology changes rapidly and also Intel just came out with a new 6 core processor, I am sure the 4770K will be more than enough though.
Kenny