Waiting for the R5 ryzens to come around to build one for my friend. Now the question is, which mobo.. was thinking the B350 Pro4, what do you guys think?

Either Taichi or Fatal1ty... that would be a nice to have in the review.

Corsair PSU's generally are pretty decent. Even the lower Wattage models can handle higher consumption and hold the voltage stable.

I felt totally in love with this case, will look awesome in my living room as my badass Steam Box. Apparently they got it designed by BMWDesignworksUSA and ASRock.
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I would stay away from ECS! Very el cheapo full of issues... Go with ASrock, much better choice.

There are some "hybrid" HDD's with SSD memory, you can install the OS in the small SSD memory and leave the rest on the HDD.

I would say 970 are a good choice if you do enjoy more silent operation. Some models actually shut down their fan in idle! But again, some brands had their fair issues with that tech...