Entering Biostar with their new model TB250-BTC that is apparently intended for GPU mining rigs with up to 6x video cards and to additional 4-pin Molex power connectors onboard, just like on the AsRock Pro BTC series. To our knowledge this is the first motherboard intended for 6x GPU mining rigs with an up to date chipset, based on Intel B250 and supporting socket 1151 CPUs and DDR4 memory. The motherboard even has an M.2 slot available for installing onboard SSD modules, a feature that might also be interesting for some GPU miners. The only problem with Biostar as a brand is the limited availability on many markets or the total lack of such, unlike AsRock that is available on much more markets worldwide. The Biostar TB250-BTC in not the first attempt at such a solution from the company, they previously had the Biostar TB85 motherboard that also came as an alternative to AsRock's H81 Pro BTC, but it never got too popular since it was also hard to find on many markets and was more expensive.
It is not like there are no other interesting alternatives available to the popular AsRock H81 Pro BTC motherboard with more recent chipsets, but since they are not designed for GPU mining rigs specifically they may not all work or may need some special settings and tuning. There are some interesting motherboards with the latest generation chipsets from Intel such as B250/H270 that come with 6 PCI-E slots and at a good price, though they may need some tinkering with the BIOS settings in order to make them work properly for mining. The price is important factor when building up a GPU mining rig and you don't normally want to spend that much on a motherboard and CPU, especially if you don't need any of the extra features or performance provided by the more expensive solutions… lower cost means faster ROI.
If you want to take a look at these alternative offers for possible good choices for 6x GPU mining rigs take a look at the offers from AsRock, Asus and MSI with B250/H270 chipsets that do have 6x PCI-E slots. On these however you need to switch the PCI-E to Gen 2.0 or Gen 1.0 and also force the TOLUD or Top Of Lower Usable Dram setting in the BIOS to 3.5 GB manually and not leave it to Auto mode as it is by default. You may want to make sure that the BIOS of the motherboard you go for has this BIOS option available, as otherwise the operating system may have issues properly assigning resources for all 6 GPUs and they many not work.