If i was to save about $100 on my build by getting the i5 would i be loosing performance in my pc ? & if so how much
More aboutintel core 4670k intel core 4770k
This explains what you will be losing. The i7 will give you more performance and can overclock to a higher speed, therefore it will be longer before you have to upgrade your CPU and you may save money in that sense.
HyperThreading adds 30-40% performance in heavily threaded code. For most gaming and everyday computing, it makes little to no difference since most of it is lightly threaded at best.
Gaming wise, there's not a huge difference between the 4670K and the 4770K. If there is, it's barely noticeable. If the programs use multiple cores, such as Photoshop, then there's a noticeable difference between the two.