Soothaa,

I spent a good bit of the day futzing with that machine and I'm convinced that it's just not going to support 7 cards until MSI releases a new bios that's going to allow us to disable the SATA controller. I have several z98 boards from them that support 7 cards and in each case, the option that allows use of the 7th card is the ability to disable the SATA controller.

With 7 cards on the z170a, you can get 7 cards to show up in the OS and Claymore but as soon as a stress is put on the cards, you start to see weirdness with the OS like hangups or dropping network. I believe this is due to a resource constraint. Possibly interrupts or memory addresses. I went through the OS and ensured that everything that could be disabled was. That included: Audio, HPTimer, and the Serial port. Could be that the next BIOS from MSI fixes things. Only time will tell.

The highlight of the day had to be the new USB risers. Back in 2013/2014, those were crazy expensive and difficult to get. Now days, they're cheaper than the risers I bought years ago. These new ones popped right in and replaced the older risers AND the jumper wires I'd had to put in the PCIe slots to force the motherboard to see the cards.