2 questions about potential builds

[egru]

This is Eric from NetSPI. I wouldn't use that guide to build a box anymore. It's outdated and was built off of what bitcoin miners were doing. You'll need enough memory to at least match what's on your cards and the processor should be anything better than a celeron. The risers are probably fine and the motherboard is ok. That case is really terrible because the fans are backwards and the only way to fix it is to move them around, but then you're blocking cables from the PSU. We figured that out too late which is unfortunate. It still cools, but is bad for reference cards.