Here is an article reviewing various steam machines, using i3's, i5's and even i7's in more premium units. The gpu's are nvidia gtx 750ti's, 970's and 980ti's. Ram varying from 4-16gb.
http://www.gamespot.com/articles/steam-machines-first-impressions-the-specs-prices-/1100-6425734/
Basically the same as budget to midrange gaming pc's except in a more compact case running valve's steam software. It's difficult to compare to consoles to pc's, they're not really the same. A smartphone has quadcore cpu's yet nowhere near the speed/power of say an i5 or i7 in a desktop. As others mentioned consoles are pretty much a one trick pony and highly optimized to do the task they're intended for. Being able to play dvd or bluray and stream netflix...