Ketcchup

Mostly when someone wants to buy a Pentium g3258, an Athlon 860K is a much much better alternative

Doubt it with a 2 VRM setup... It will allow to overclock but your VRMs will throttle when you apply some voltage. Go with an ASRock H81M-HDS, it has 3+1 VRM setup that will allow you to push voltage without risks. Adding some ebay's mosfet heatsink would be superb ,but not needed really. PS: If you haven't bought G3258 already, get an i3 and a cheap mobo. Those extra threads will help INMENSELY in modern games.

Pentium N3540 is better, but I guess you have límited budget

The extra threads from i3 are vital to avoid stuttering in 4 thread games.

1080p without stuttering clearly. 30fps is "normal", stuttering is anonnying.

Pentium is good in 1-2 thread games, in 4 thread games suffers from stuttering and frame dips. My suggestion is to go with an i3 and a cheap mobo, or 860K with a decent mobo like A88XM PLUS or PRO

What's the difference between this and 3DNAND?

Give us more information; - CPU? - Current Heatsink? - Photo of the Case (inside)? Maybe there's no need to buy anything and just some cleaning and cable management is needed

An SSD can be added in the future, a soldered CPU, not.

10m HDMI (or ethernet)cable across the walls/roof using this (don't know name in english, in spanish is Canaletas).

Yes, thermal margin is the distancd to the maximum temperature defined by AMD, which is 70 degrees iirc

Matches it in máximum fps, at minimums pentium is terrible

APU sensors AREN'T FIABLE WITH 3D PARTY PROGRAMS! Only AMD OVERDRIVE is fiable. There is a bunch of info in internet CPU socket temperature is fiable too

Exactly, but there's no big difference between 860k and fx6300. Sure 860K has 15% more IPC, but it's neutralized by the lack of l3 cache and a decent memory controller. Anyways fx6300 needs a good mobo, 860K just needs a decent one (like a88xm-plus)

i3 will be far better, specially in gaming