One thing that was made perfectly clear in AMD’s briefing on the new Athlon was that this is not a performance part – due to the nature of Excavator the new CPU would be purely an efficiency play, allowing customers to take advantage of the latest architecture in the desktop if they didn’t need the full-fat performance.
Price says it all. At 70$, It won't certainly not beat the 10$ more expensive Athlon X4 860K.
This chip is a way to play on the Carrizo, Streamroller brands and to recycle chips that don't make the deal on mobile parts like Petykemano said.
But if you look a gaming review between the X4 860K and the G3258, I don't think there's lot to hope about the X4 845 :
We'll see with the incoming reviews (it's weird to laucnch a CPU with no review at all) which was really rare on the Kaveri side.