Question Which motherboard can support 3 x RTX 2080 Ti without blowing up?

Mar 13, 2019
I'm building a rig with 3 GPUs, at least 3 x RTX 2080 Ti (TDP 250W). May also swap out one of them for a RTX Titan (TDP 280W). Not for gaming, but deep learning work. CPU is also pretty high end, like a i7-9700k (TDP 95W).

Is there a way to check how much "load" a motherboard can take, as we are talking almost 1000W TDP. Also know that this rig may be running on full load for CPU + 3 x GPU for extended periods. I've looked at motherboards like the ASUS ROG MAXIMUM X APEX, and it has 3 GPUs slots.

Also, I've read about "half-capacity" PCIe lanes (x16) vs "full-capacity" PCIe lanes (x32), which can affect GPU performance. How do I check that a motherboard can operate all 3 PCIe slots at optimal settings? Thanks.