bottleneck performance?

[KarstenS]

Slot 1 16x - No GPU
Slot 2 16x - No GPU

You can put a GPU in either slot and have it work in 16x PCIe

PCI-E x16 slot doesn't mean it is connected with 16 lanes Read the data sheet carefully. Before I did my mobo update, I've read many of them. And all had something together: Not every slot can operate in x16 mode.

From my research, it typically looks like this:

Boards with 1 PCI-E x16 Slot the slot is typically connected with 16 lanes.

Boards with 2 slots that supports CorssfireX, slot 1 is connected with 16 lanes and slot 2 is connected with 4 lanes.

Boards with 2 slots that supports CrossfireX/SLI, slot 1 is connected with 16 lanes and slot 2 is connected with 8 lanes.

Boards with 3 slots (likeke my actual board) that supports ossfireX and SLI, slot 1 is connected with 16 lanes, slot 2 is connected with 8 lanes and slot 3 is connected with 4 lanes.

Boards with 4 slots that supports CrossfireX/SLI, as i could see, 2 slots are connected with 16 lanes and 2 slots are connected with 8 lanes. But if the slots with 8 lanes are filled, the slots with 16 lanes will operate in x8 too.

So if you need PCI-E at x16, you must put that card into a slot with 16 lanes and watch out to leave partner slots empty. Regular, there is also a warning in the manual to tell exactly this.

PCI-E 3.0 standard starts at x8. Its not fixed to x16