As far as the AMD FX 8350. I will be buying one of these around september to upgrade from my Athlon II x4 620 2.6Ghz quadcore to a far more powerful CPU. Benchmark results for the AMD FX 8350 place it up there with the Core i7's as shown here:
http://www.cpubenchmark.net/cpu.php?cpu=AMD+FX-8350+Eight-Core . This is the most powerful CPU I can put into my motherboard.
As far as the Core i5 4670k, it benchmarks weaker as shown here:
http://cpubenchmark.net/cpu.php?cpu=Intel+Core+i5-4670K+%40+3.40GHz&id=1921I have bought AMD as well as INTEL products over the last 20 years, and even if the Piledriver is a hot running electron hog, I'd go with whatever gives the best results for money paid. Intel has always been slightly more expensive although with promo's etc it can sometimes be cheaper to go with Intel.
Just a few weeks back the AMD FX 8350 was just $179.99 through newegg.com and I should have bought one, but I held off since my wife is out of work for the summer and the Athlon II x4 620 2.6Ghz quadcore is plenty for my computing needs anyways with games etc. Since then i have also seen it for sale in original unopened box on amazon for just $149.99 and was also tempted to buy that one, but held off. Come September, I will buy one of these as a birthday present to self
Also I am not a fan of Integrated Graphics, mainly because I game a lot and have yet to experience an integrated graphics GPU or an APU that is all that!
Even with the APU's they are no wheres near the performance of adding a high end video card, but if you are on a tight budget build you can go with an APU and play games on normal settings possibly, but wanting Ultra High Graphics settings combined with high resolution, and a fast frame rate may not be achieveable with an APU depending on what game is running.
For my gaming I am using a mixture of settings to get by with a bargain video card. I am using the AMD Radeon HD5450 with 1GB DDR3 which cost me just $30, and I found that using a screen resolution of 1024x768 with this card allows me to set my graphics settings higher in World of Warcraft on HIGH and get a 30fps frame rate. Setting it on Ultra though is not very desirable with 16-20 fps as well as I get a surging effect where the screen speeds up and slows down in a frequent interval. Prior to this I had my screen set to 1280 x 1024 and was only getting 22 fps on HIGH settings and Ultra settings were in the dumps with 12-15 fps and freeze framing. Fortunately by the time I need a better video card, a newer more powerful videocard would have made its way down to the bargain price range of less than $40. The only thing I did have to do though I mount a 80mm fan to the inside of my tower to blow cool air across the face of the passive heatsink. This 80mm fan would outlive many of the smaller fans that come bundled with the video cards. I have had bad luck with video card fans failing and killing the video card when you dont realize they are not spinning and from good name brands like XFX, BFG, and ASUS. The small fans seem to last only 12 to 18 months of heavy gaming and then they seize up and kill the video cards. I haven't had good luck with the video cards that cost me $120 to $200 mainly due to their small fans failing, so I went the cheap route and add my own cooling fan and the video card is about 2 years old and still chugging without any issues happily cooled by the 80mm fan that is powered off the the unneeded floppy power connector with wire stripped back and inserted for the 12VDC and electrical tape to keep wires in connector. GPU temp stays happy at below 55C in an a 70-75F room.