What kind of 3D rendering are you going to be doing? You're not gaming, obviously, so what are you running on a mining machine that requires 3D rendering?
Because if you ARE doing involved, demanding modeling or rendering, and those cards are connected via x1 or x4 cabling, they may not even be capable of doing what two or a single card can do when installed in a standard x16 PCIe 3.0 slot. I'm not too sure on that, as this is a somewhat new "problem" that honestly I've not seen here before or in the real world. Generally, mining configurations are used for mining, other configurations are, well, not used for mining. At least when we're talking about 4+ card configurations. Typically a high end video editing, CAD or graphics centric machine wouldn't even use more than a single card anyhow in most cases so it's an unusual dilemma to say the least.
Also, if that is the case, then there is definitely the potential for a MUCH higher power requirement since the 8 pin PCIe connector is capable, by spec, of delivering 150w or more, each, compared to the 75w of the 6 pin, and with 4 x75w slot power plus 8 x150w PCIe power AND generously figuring 200w for the rest of the system, you are looking at needing more like a 1700w unit, although I am doubtful that those cards connected by slots that are not 16 lanes will be able to draw that much. It would probably be wise to know a lot more about the what and how regarding what you plan to do before making any further suggestions or offering any kind of definitive advice.
Facebook
Twitter
Instagram