Asus Zenith x399 SLI Setup w/o Slot #1

[czyzer]

Just purchase an Asus Zenith x399 motherboard, along with a threadripper 1950. For cooling I purchased a Noctua NH-U14S TR4-SP3. Come to find out after the fact that the Noctua blocks the first PCI express slot (it's called out on their site, I didn't see this when buying). I have two Asus Rog Strix 1080 TI's I'd like to run in SLI mode.

Looking through the manual, it appears there is no way to run two cards at x16 without including slot #1. Is this correct or do other slots switch based on the usage of slot #1?

The Asus x399 reports it's PCI Express configs as: 4 x PCIe 3.0 x16 (x16, x16/x16, x16/x8/x16, x16/x8/x16/x8) *1.

Per the manual the 4 slots are labelled as (from top to bottom): PCIEX16_1, PCIEX8_2, PCIEX16_3, PCIEX8/X4_4.

 

[LucaFire]

Each PCIe slot has a maximum capability - some have a max of x16 lanes while lower ones are maxed at x8 lanes.
Your motherboard has four PCIe x16 slots... so you should be fine not being able to use the first slot. The other three have x16 lanes (according to the Asus website).

But seeing as they are labelled as so, yes, you'll be able to run the OC but you'll only be able to use PCIe x8 and PCIe x16.