So thanks to lightning I am in a situation where I must replace my mid-2011 Quad Core i7 iMac. I was told that today's i5 quad core CPU's may perform better than 2011 i7's. How much truth is there to this? Though I may not need or even use the horsepower, I do not want to leave myself short on the new unit. Recommendations? ( it looks like the i7 iMacs are not on the shelves yet so I am looking at the i5.