Any good fm2(+) CPUs better than AMD Athlon x4 760k?

Right now, there is not FM2+ CPU/APU that will be a noticeable upgrade from the 760K so upgrading to Intel will be your best option.

Technically, any CPU and any GPU can bottleneck each other to some extent, but 760K will do fine with the 270X - there will not be any serious stutters, but you will want to get an Intel CPU down the road if you will keep upgrading your system.
 


That all depends upon what you want to do with your computer. Socket FM2+ are fine computers but your going to be on an APU. APUs are for general computer users who only play very light games (non AAA titles) and are primarily looking for a very good general computer that is no muss no fuss. APUs use very little power and need very little cooling when compared to gaming computers. If you upgrade to an APU the computer is what it is from the time you buy it. The best advantage they have is a good GPU and CPU bundled in one chip. The downside is putting a dedicated GPU in it defeats the purpose of an APU and the CPU will more than likely bottleneck a dedicated GPU upgrade. If you looking for a gaming rig better to go with the "enthusiast" line of processors with a dedicated GPU.

AMD's enthusiast line (FX) is a little long in the tooth but totally competent to game at mid - high levels @ 1080p (even at 1440p for some games with proper GPU). What motherboard do you currently have? If AM3+ you could upgrade to FX 6300-83xx and would be a large improvement over your current rig. If your on older AM3 and have to replace motherboard anyway you are better off to either wait for AMD Zen or bite to bullet and upgrade to Intel. Or you could see if you could get an AM3+ board super cheap and go for FX. If you upgrade to Intel or Zen either of those is going to cost quite a bit as you will have to buy new motherboard, processor, more than likely psu, depending on the generation you upgrade to RAM (Skylake and Zen are DD4). Upgrading to Intel or Zen will be basically building a new computer.
 
If you overclock: i5-4690K + MSI Z97 PC MATE motherboard - $300 (plus cooler)

If you don't overclock, go with Skylake (will need to get DDR4 RAM): i5-6600 + MSI Gaming B150 + RAM = $350

If you don't overclock, go Haswell (still good): i5-4460 + H97 4PRO for around $250-260

If you do a lot of video editing, rendering or hardcore streaming: Xeon E3-1231 V3 + H97 4PRO for around $320