Let's talk CPU's/cores.

[Sannakji]

So in the next few weeks we are seeing Intel's new flagship 4 cores and AMD's new APU's coming out. I may build soon and I've been struggling with deciding on a cpu.

I seem to recall reading Dolphin doesn't really multithread too well due to the difficulty of implementing that. So is a 6700K the best choice? What about an older six core Intel, like the 5860K? Their individual cores are clocked much slower. Could an APU by itself with no dgpu get decent fps on some games, with enough RAM? Does Dolphin recognize crossfire between an APU and dgpu? 

[ExtremeDude2]

Dolphin doesn't use multi-GPUs

[admin89]

APU is a no go if you care about graphic like me
Even if you overclock CPU to 5.0GHz ,iGPU to 1013MHz , Ram to 2133MHz like i did , it will not handle any higher than 2xIR (720p) in demanding games
In the end , APU would be a waste of money and you would pick up a dedicated GPU anyway
Current FX 8350 @ 5.0GHz doesn't perform as good as i3 4130 @ 3.4GHz in Dolphin Benchmark . So don't hope new APU will make huge boost in performance
And btw , A10 7850k isn't any better than A10 6800k except the power consumption
The best CPU for Dolphin atm is the CPU that has the highest single threaded performance plus highest clock speed (i7 4790k with auto turbo to 4.4GHz)

[yorkiesandskittles]

I'd go for the Pentium G3258 and either an R7 260X or a GTX 750 SC. Even if the i7-4790K does perform better in Dolphin, it is still not nearly worth the huge price difference.

[Sannakji]

I've got the funds. So Dolphin only uses 1 or 2 cores? Any benefit of an older six core over the bleeding edge 6700K four core then? DX12 is out soon. When is Dolphin implementation planned? Have to balance PC gaming and Dolphin gaming so I do have to consider DX12 in this too...

[ExtremeDude2]

An older 6 core won't be as fast as a newer 4 core.

[Garteal]

So in the next few weeks we are seeing Intel's new flagship 4 cores and AMD's new APU's coming out. I may build soon and I've been struggling with deciding on a cpu.

I'd go with Skylake unless a miracle happens for AMD.

I seem to recall reading Dolphin doesn't really multithread too well due to the difficulty of implementing that.

It's already as efficient as can be at the moment. The FAQ explains this pretty well so I'd suggest reading that.

So is a 6700K the best choice? What about an older six core Intel, like the 5860K? Their individual cores are clocked much slower.

If you go by the leaked benchmarks (which you should take with a grain of salt until proven otherwise), it will be the best CPU for Dolphin when it releases as it'll be a bit faster than the current top CPU (4790K).

Dolphin only really uses two cores (three when you force LLE on a separate thread) but you will get a rough improvement of 20% in performance if you use a quad-core CPU. Beyond that no improvement in performance has been measured, so go with a quad-core unless you need a hexa-core for other purposes.

Does Dolphin recognize crossfire between an APU and dgpu?

No.

[AnyOldName3]

I've got the funds. So Dolphin only uses 1 or 2 cores? Any benefit of an older six core over the bleeding edge 6700K four core then? DX12 is out soon. When is Dolphin implementation planned? Have to balance PC gaming and Dolphin gaming so I do have to consider DX12 in this too...

Dolphin isn't likely to benefit much from DirectX 12, as Wii and GameCube games don't have anything particularly hard to render. If it turns out that there's some way it'll help, we won't know until there's a public release of the SDK, which won't happen for a while. Also, quite a few of Dolphin's devs prefer OpenGL to D3D, so it's more likely that that backend will end up with OpengGLNext/Vulkan features before DX12 is implemented.

[NKF98]

I've got the funds. So Dolphin only uses 1 or 2 cores? Any benefit of an older six core over the bleeding edge 6700K four core then? DX12 is out soon. When is Dolphin implementation planned? Have to balance PC gaming and Dolphin gaming so I do have to consider DX12 in this too...

Dolphin uses 2 (sometimes 3 with DSP LLE on separate thread) cores. I would suggest an i7-4790k if you're rich, or the Pentium previously mentioned if you're not. i5-4690k is a good middle ground, both the i7 and i5 mentioned will do good on PC games.

[MayImilae]

Dolphin only really uses two cores (three when you force LLE on a separate thread)

Technically, that setting has been removed, and it auto-enables whenever it's safe.