Right now I'm just playing with the idea, I've always only considered starting with a Asus B250 Mining Expert with 13 + 6 GPUs and have it mining two different coins. The idea of having 19 GPUs in one portable frame just seemed better than any other solution with less GPUs.
Considering that, is there nevertheless any benefit going for the Gigabyte B250 instead?
Let me save you the headache. There is nothing wrong with the Asus B250, except that going beyond 12 cards will give you grief. Don't go beyond 12 cards on any MB currently out now. There are only 12 usable pcie lanes with the B250 chipset. Go beyond this and you will have reliability issues and your CPU will work overtime trying to keep it together. The Asus MB is nice, but confusing and since 12 is the maximum pcie lanes, save the money and get the Gigabyte board. It works right out of the box, you don't need to even hit the bios, just load the OS and start mining. Ignore the directions to plug in molex connectors or more than one PSU to the board. Just use the 24 pin MB and 8 pin CPU connector and that's it. I have two of these fully loaded. One more piece of advice, don't skimp on the CPU like with a Celeron, get a decent one like the i3-7100, otherwise you'll be pegging near 100% while mining and it'll feel sluggish. My i3 is at 60% utilization, 12 lanes is a lot for one chip to handle, night and day from just 6 cards.
https://ark.intel.com/products/98086/Intel-B250-ChipsetThanks a lot for the advice, a completely different approach to look at. Though completely OT concerning my initial question, I have more questions for you:
Limiting the number of GPUs to the number of available PCIe lanes totally makes sense of course. I could imagine starting with one such Gigabyte rig and adding another one later.