- "Cores" are not all the same. Some cores perform better than others. It's the throughput of the individual cores that matter. As an analogy, think of two 4 cylinder engines running on regular gasoline. They both have the same number of cylinders and run on the same fuel, but one delivers 150 hp in a sports car ( 2.7 litres, turbo charged, fuel injected, etc) and the other delivers 48 hp in an old farm tractor (1.8 litres, carburated). SImilarly, you can't compare CPUs solely based on the number of cores and the clock speed.
- The FX-4300 doesn't have 4 "true" cores. It has 2 "processor modules" that each have 2 lesser cores that share some resources like a floating point register, etc. The FX-4300 is more equivalent to an Intel dual-core i3 with HyperThreading.
- In almost all gaming tests, an Intel i5 outperforms any AMD processor, but an FX-8320/8350 comes closest. The FX-8320/8350 is sometimes referred to as an "8 core" processor - but really it's a 4 "processor module" processor.
In any case, you gave no indication of your budget in your original post, so I was just trying to give you options that would increase the machines performance. Within your budget, that FX-4300 with GT-730 is about the best you'll find. I'd still suggest you try to spring for an FX-6300 at least. GW2 is a very CPU bound game and you'll find that an FX-4300 will stumble in crowded areas.