Link to GPU boss comparison Those two are almost identical in performance, it is possible to crossfire a discrete card with the APU, but I have never done it, something you may wish to look in to and research.
You confused the 8570 desktop graphics card with the 8570d which is the igpu on some a8 apus. The 640 is almost double the performance.
I'm sorry if I wasn't clear, but I had meant the 8570D, which is the iGPU on the A8-6600K APU from AMD.
I have personally had a better expeirience with nVidia for graphics cards. Also, I'm looking to convert my system to Intel platform (it currently has an A8-6600K with 8570D) with a pentium G3258 and a MSI motherboard. Micro Center is offering a bundle for them for a steal, so I thought this would be my chance.