I'm working on a build right now ($450-$500) and I'm deciding weather I should buy something like the <a href="https://teksyndicate.com/videos/kill-your-console-build-2-600-gaming-pc">Kill Your Console $600 Build</a> or something similar with a Kaveri APU and a cheaper 7770/R7 260X. The cheaper option would be the Athlon as the <a href="http://www.newegg.ca/Product/Product.aspx?Item=N82E16813128656">FM2+ mobo I was considering</a> was $90. Now that's pretty overkill and I could probably get one for $70-80, but <a href="http://www.newegg.ca/Product/Product.aspx?Item=N82E16813128656">this FM2 mobo</a> (the one that was used in the Kill Your Console Build) is $45 after rebate. Of course we really don't know what the prices will be on the Kaveri APUs, but my estimate would be around $150. I already have 2133hz RAM, which would help the APU performance greatly. Also I live in Canada, so if you want to provide store links, please put them on Canadian sites. Thank you!
I would invest in a AMD Athlon x4 760k, its just a 750k just .4GHZ faster. It's only $10 more, if you can spare the change. I don't think a 7770 or a R7 260X would give you a satifying gaming experience, the R9 270 or 270X would be much better.
If you haven't bought anything other than the ram, you might consider this guide:
AMD doesn't have hyper-threading.
My mistake, it's advertised to have Hyper-Threading.