Threadripper 7 PCI-E slots



As of this date, these are the only X399 motherboards available: http://www.tomshardware.com/forum/id-3505087/tr4-motherboards-x399-comparison-tables.html

The motherboard that has the highest number of PCIE x16 slots (at 5x) is the Gigabyte X399 Aorus Gaming 7 (though only 4 slots are PCIe3.0 at x16/x8/x16/x8, while 1 slot only runs at PCIe2.0 x4). This is similar to the Asus ROG Zenith Extreme, though with only 4x PCIE x16 slots (runs in PCIe3.0 at x16/x8/x16/x8) has an additional PCIe2.0 x4 slot (x4 physical slot).
 
Right. At this point you'd have to use PCIe risers to connect all those GPUs. The MSI x399 carbon I'm on currently has 6 PCIe slots, though two of those are x1 and two are electrically x8...not that you need x16 for GPU rendering. In short...get PCIe risers/ribbon cable extensions and be happy with 6 GPUs for now.

While the Giga board does have one more x16 slot it won't help you, because three of those slots are too close to one another to allow more than 2 double wide GPUs in them anyway.
 
Sure, LTT had a video of a computer with 7? single slot GPUs on a single mobo too...think it was centered around GPU pass-thru for VMs. There are definitely a couple options out there, but they're expensive and selection is extremely limited. If you just want GPGPU compute performance you won't require x16 or even x8 bandwidth to the GPUs though. As a result your options open wide and you can just use PCIe ribbon cables to connect GPUs to PCIe slots.
 
https://www.anandtech.com/show/11685/amd-threadripper-x399-motherboards

"In total, AMD has stated that the platform can support six GPUs maximum."

I just wonder is this true that it can only support 6 gpu's even if it has 64 PCIe lanes?