ericman2001
Space Marshal
I might have to disagree with you here. I don't know what Montoya's average use is like, but for Star Citizen you'll likely see no benefit from an i7 over an i5. The reason for this is that HyperThreading does not actually provide an additional four cores to your system, but instead only provides faster context switching. If your average usage is processor heavy, as I imagine Star Citizen is, then HyperThreading won't actually do you any good.Oh, and as for the upgrade: even buying the 770 you're probably still going to want a new graphics card by the time Star Citizen comes out... so I'd recommend downsizing the card and putting $50-$100 of that into a faster CPU like an i7. That'll last you several more years unlike the graphics card.
As an example, look at benchmarks between an Intel Core i7 (four real cores) and an AMD Vishera (eight real cores) processor. The Intel part crushes the AMD part in any single threaded application. It's not even close. But when you throw 8 threads at the processors, AMD keeps up pretty well. If the HyperThreading units were as equally good as the regular cores on the Core i7, it would dominate over the Vishera in multithreaded tests, too.
Further, look at what HyperThreading gets you: you get some extra registers, a little more L3 cache, and maybe a little more flexibility with process scheduling. What you don't get are 4 more execution units. On that basis alone, logically the i7 is incapable of running 8 processes simultaneously without some entering a wait or sleep state at least some of the time.
Now, that being said, if you run software that has lots of sleeps or waits and is heavily parallelized, then an i7 would be great. Software compilation for one benefits well. Or web servers. If you have that kind of usage profile, get an i7. Alternately, if the i7 has some feature you need that the i5 doesn't, obviously spring for the i7. I haven't memorized their feature list, so I don't know everything that's different.
Some comparison between an AMD FX-8350 and a Core i7 3770, you can check out Anandtech. You can clearly see where HyperThreading wins big and where it doesn't work so well. If Montoya is going to do lots of video encoding and Star Citizen, I'd say the i5 is a fine choice. That or an 8-Core Vishera, while recognizing that a similar cost Intel part will decimate it in single threaded performance.