Recently, a lot of miners are struggling to find appropriate motherboards for the mining operation. Some motherboards might work with the certain quantity of cards and some may not. There are already tests and reviews online confirming that 7 GPU motherboards do work (such as MSI Z170A Gaming Pro Carbon). But note, however, chipset Z170 is old already and being superseded by Z270. In near future, you may have a hard time finding Z170 boards.
Luckily, in our NVIDIA test lab, we stumbled across an interesting motherboard that has seven PCI-e slots and two M.2 slots that support PCI-e up to x4 for M.2 SSDs. Asus PRIME Z270-A goes for around 150 EUR in Europe and looks very promising at first glance.
Other interesting pieces of hardware are KFA² GeForce GTX 1060 OC 3GB cards (for 180 EUR in Europe) and slightly better cooled KFA² GeForce GTX 1060 EXOC 3GB (190 EUR in Europe). It has been known now for a while that NVIDIA GeForce GTX 1060 are very popular for Equihash mining on NiceHash as these are cards are cheap, fast and consume very little energy. Achieving 260-270 solutions per second with only 75 W TDP is no problem and can be done with only slight overclocking modifications.
We decided to put together Asus PRIME Z270-A and eight KFA² GeForce GTX 1060 EXOC 3GB video cards. We did update motherboards BIOS to the latest version and enabled 4G decoding. Everything else was left as stock. Once Windows 10 loaded up and after a bit of waiting for drivers to be installed, we saw all 7 cards in device manager.
We used one of the M.2 slots for the hard drive. Why? The price of M.2 SSDs is not so huge anymore; we got our Intel 120 GB drive for only 60 EUR. There is less hassle around - no need to deal with SATA cables anymore, just stick SSD into M.2 port. Additionally to that, these drives are usually also faster.
We turned another M.2 slot into the PCI-e slot by using cheap M.2 to the PCI-e adapter that can be purchased from Chinese sellers on Ebay.
On another motherboard we have had no luck getting additional GPU working when using this adapter. But fortunately, it worked on Asus PRIME Z270-A.
Our complete setup looked like a giant octopus, but it was enough to boot into Windows and see all eight cards detected by the device manager.
We also checked with GPU-Z and all cards were successfully detected and linked with PCI-e v3.0, which is another bonus compared to other motherboards that usually work with 6+ cards only under PCI-e v1.1. The higher bandwidth speed may not look like an important factor, but the slower link can take 1-2% off of card's performance, especially in algorithms that are sending a lot of data from/to CPU/GPU.
Next time, we will test how NiceHash Miner works with eight cards and how much you can earn with the "NiceHash Octopus".