be careful with the 1 a week thing get processor and mobo last then if you go to put together and they are bad and it's after 30 days. Well just be careful. Trust me you don't want to go through that you may end up getting a new one put I wouldn't chance it.
How much faster is sandybridge? Do you know what it was designed for? Is it also faster clock for clock (same speeds)?
It's the same as before. The i5 is primarily a gaming CPU whereas the i7 can handle media encodes, rendering and the likes a lot better. Typically Sandy Bridge is about 10% faster per clock compared to the earlier i5s and i7s. They are, however, higher clocked. An i5/i7 will typically be from 2.66Ghz to 3.06Ghz at stock, and will overclock to around 4.0-4.2Ghz. Meanwhile a Sandy Bridge CPU will typically be clocked from 3.0 to 3.4Ghz at stock, and will overclock to around 4.7-5.2Ghz (4.7Ghz is even attainable on the stock cooler for the 2500K). So overall, you're gaining up to 40% if you go for a big overclock. It's worth remembering though, that only the K CPUs (i5 2500K and i7 2600K) can actually overclock at all. They are well priced, but the cheaper models cannot overclock, so beware when looking into them.
