Is the RE6 x299 3 or slot SLI bridge?

[rondocap]

Trying to figure out if the best sli slots are 3 or 4 slot for this motherboard for the sli bridge.*

[Silent_Scone]

As per the manual, the optimal lane configuration for two card configuration is PCIE 16x\x8_1 and _3 (slots 1 and 3).

[Quozzo]

There's a 2 slot SLI bridge in the box that doesn't have connectors for the nonexistent card in slot 2, if you're using 2 way SLI.

[Textret]

The spacing is 80mm. What it is called depends on who's bridge you are using. EVGA, Zotac, and Gigabyte call it "2 Slot Spacing"; Nvidia, MSI and Asus call it a 4-slot configuration for their bridges.