Sub $400 Silent 4k@60hz SFF PC

We're loving this simple yet effective passive build featuring ASRock's J5005-ITX motherboard, a Morex 557 Universal Mini-ITX case, a Mini-Box picoPSU-80, and a Samsung 850 EVO SSD. Affordable and perfect for Youtube and Netflix 4K content.

Thermal performance is just fine thanks to the large heat sink, but mostly thanks to the Morex mesh panels (yes, that's more important). For the record, the low-power Pentium J5005 is as powerful as the legendary Core 2 Quad Q6600.

Source: reddit