It seems that the race for a mining motherboard with the most PCI Express slots is far from over with the AsRock H110 Pro BTC+ and Biostar TB250-BTC PRO probably being only the start. It seems that Asus is planning on joining the party with not 12 or 13 PCI-E slots, but with 19, though you might be limited to actually using only 16 of them. We already know that you are limited up to 8 GPUs from a kind (AMD or Nvidia) under Windows, so 16 max if you mix them. With Linux though more GPUs from a kind that what Windows allows are usable, but then again more than 16 at this point might not be possible. This is probably why Asus are talking about this product as supporting 16 GPUs even though it does come with 19 slots…
For now Asus is just teasing us with this motherboard and there are no full details about it, including info on pricing and availability. Still it shows that the company has interest in the mining market, especially after also releasing mining oriented GPUs. Unlike some other manufacturers however Asus is showing that they are designing their mining products with miners in mind and not just pushing something that is not worth buying like some others. Their Asus B250 Mining Expert mining motherboard comes with three 24-pin ATX power connectors for directly connecting up to three power supplies without the need to use external means to synchronize the PSUs. There are also three 4-pin Molex power connectors on board for powering GPUs, though you probably will use powered risers and won’t be needing these.
We are yet to see more information emerging, but things are definitely looking interesting already. What you need to be prepared with motherboards for mining supporting so many GPUs is that there will be some unexpected challenges when building the mining rig. Cable lengths, connector spacing, enough space for proper cooling and so on. Design challenges emerge and the more video cards you use, the harder it gets to make things work as expected. Though once you clear the design for let us say 16 GPUs, then the next mining rig should be much easier and problem free to assemble… hopefully.