Best overall gaming performance for 700. Just pc no windows. Do not care about looks
It's really close to 700. You can scale back the CPU to a 6400 to make up the difference or the GPU back to a 380x.
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If you dont need a monitor, i would replace the r9 380 i chose with a r9 390. Otherwise, this is your best bet for gaming performance in this price range. However, the monitor i chose is really nice, low latency, IPS 27 inches by LG (lg makes killer displays)
Assuming you really are most concerned with raw performance, and not visual quality, you'll want an overclocked i5 with overclocked memory, and ideally an SSD or hybrid drive (take your pick ~240GB SSD or 1TB hybrid).
BCLK overclock the i5 with the following build:
Use lower visual quality settings and the above can achieve very high performance in most games (100FPS+).
If in fact, you aren't actually interested in a build that prioritizes performance, but rather, a good balance of performance and visual quality (by most standards), then consider something like this