Dx12 is going to get rid of the driver thread(driver/api overhead) ,games today have 4 threads MAXIMUM (threads that get high % so are essential for speed, caused by ps4 hardware the main threads run on one of the two cpus so 4 threads max) vga thread included,so dx12 is going to make slow quads even more redundant than they already are because there will be even less threads to run and dual cores will become even faster for the same reason.
I can't even right now...
Many NEW titles support 4 cores/threads as standard and a bunch of them even go beyond 4 cores.
And yes, the overhead reduction will benefit core 0 the most...but that does not change the fact that games from this year and on will be optimized to actually use 4 threads...or even more.
And guess what...if 2 cores have to do the work of 4 threads...then even "slow quads" suddenly stand a chance again.
Look at this....even a dual core with hyperthreading manages to be REALLY close to a 4.8 Ghz Pentium
Cores/threads matter...a lot. Those 1.3 Ghz difference are not enough to place it above a "FAKE quad core" enough to call it a real victory...now look at the real quad..and boom the pentium is in the dirt(We are talking 50% difference even though the pentium is 1.3 Ghz higher clocked and approach 100%!!!! vs the non OCd version).
Sure, the 860K is nowhere near in IPC..but while the single threaded IPC only went up a little bit, the multithread IPC of Kaveri jumped quite a bit.
And if you OC it a little it will win over the i3 and the pentium VERY easily thanks to DX12. Let's put aside that in quad core utilizing games with some OCing it can already throw down the gloves vs the i3s that are actually a higher price class. (4.5 should be possible on almost any chip with the 860K).
So if you have GAMING in mind for as cheap as possible while looking into the future...that 65$-70$ QUAD core is a solid choice...if you don't mind that there is no real upgrade path.
Obviously if you have the money...you should be taking an FX 6/8 or an i5/i7