intel i7 4770k gaming build

i5-4670K vs i7-4770K:

He means the "i5-4670K". The i7-4770K uses something called "hyperthreading" which very few games actually make use of. Both CPU's have FOUR physical cores.

I won't bother explaining HT but you can Google that.

**AMD CROSSFIRE SUPPORT**

You may wish to re-evaluate your situation now that AMD has released its first driver that attempts to fix the Crossfire issues. Games were feeling sluggish and they discovered that many times the second GPU was supplying a "RUNT" frame (short frame that's very fast). FRAPS was reporting 60FPS when in reality it was closer to 30FPS perceived. I don't believe it affects the REPORTED frame rate but it does affect the PERCEIVED frame rate. The new driver frame time fix is on by default. Many games using Crossfire should feel less sluggish now.

FAR CRY 3 tweaking:
I spent a long time tweaking this game and discovered some important things:
1) don't use AA (there appears to be anti-aliasing already applied as the game looks great without checking AA. I dropped to 44FPS from about 60FPS. I disabled AA, the game looks great and I game at 60FPS on my GTX680/i7-3770K).

2) VSYNC/GPU to ONE buffer (forget names, but if I increased to two or three buffers I got stuttering).

I'm not saying to NOT get the Intel CPU, but the CPU you do have is half decent. It's a lot of money to upgrade so you have to decide if that's worth it or not.

For the FEW GAMES that you really need a better CPU, maybe you're better off TWEAKING the settings instead as I suggest above. That may give you nearly the same experience on your current rig.

CPU Scaling in FC3:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811129181

You can see the AMD CPU's do poorly here. The FX-8170 at 3.9GHz is below an i7-3770K by a big amount. I would expect the i5-4670K to be about the same as the i7-3770K which is 27% faster. With a single card I think we're approaching a GPU bottleneck with the top CPU's here.
*I do not know how much CROSSFIRE would change these results.

I hope you find this information useful.
If you can't wait then i5-4670K plus a good 1150 Z87 motherboard may be your best bet.

**Keep in mind you should be able to OVERCLOCK your current CPU further with that newer cooler. The Intel CPU's are very power efficient but generally can't hit as high a frequency as current AMD CPU's. I think 4.5GHz is the best target for the i5-4670K though personally I run my i7-3770K at 4.2GHz since I can maintain that small overclock while also maintaining the Intel Power Saving features.

http://www.bit-tech.net/hardware/cpus/2011/10/12/amd-fx-8150-review/9

The above shocked me.
Perhaps it isn't typical and maybe the Windows hotfix helped the above (probably not), but in this game at these settings the FX-8150 at 4.8GHz is well below the i7-2600K at 3.4GHz!

I imagine the $240 i5-4670K would be near the TOP of this list if it could be compared.

games do not need a super powerful cpu like the i7-4770k. However, if you have to budget for it, definitely go for it. It is a great CPU.

This is a good mobo :http://www.newegg.com/Product/Product.aspx?Item=N82E16813131974

Slighlty cheaper but still good :http://www.newegg.com/Product/Product.aspx?Item=N82E16813131979

yes it will be good for a long time

You can easily go to the motherboard website to confirm if it is CROSSFIRE capable.
http://www.asus.com/Motherboards/Z87PRO/#specifications

Here's the info you want:
Supports NVIDIA® Quad-GPU SLI™ Technology *2
Supports AMD Quad-GPU CrossFireX™ Technology
Supports AMD 3-Way CrossFireX™ Technology

QUESTION:
Have you seen any improvements with the new AMD drivers that help fix microstutter?
(You wouldn't likely see a frame rate difference, but it should feel less sluggish. More like 60FPS instead of 30FPS in cases.)

im not too sure mate but where on the same way. im planning to get i7 4770k haswell 1150 and pair it with gigabyte z87 oc.

Z87 motherboard:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131989

Why?
Just compare the customer reviews (especially 1/5 scores). Feature-rich board with everything you need, quality, for $200. Not bad.

AUDIO is much better than any Realtek solution so no need for a sound card.