manningbowl135 :
One of my friends have just bought an i7 and he asked me why intel came out with i5. I couldn't answer him because I don't know anything about the i5. What's it's selling point? It's a bit cheaper, but not that much.
Core i5 is supposed to be the mainstream CPU, while the Core i7 is supposed to be the high end / enthusiast CPU. Both Core i7 and Core i5 shares the same cores, but Core i7 does not have PCI-E generator built in. So therefore because there are less components on die, Core i7 is able to overclock higher, with better support for multi-GPU configuration.
So in a nutshell, if you are planning to go for a multi-GPU solution, Core i7 is a much better choice for you. If not, Core i5 would suit you better.