How many PCIe lanes does Radeon RX580 use?

[jeffrey_dibartolomeo]

Sorry in advance if this has been answered, but I have searched and cannot find a direct answer.

I'm considering an Asus RX580 Dual 8GB video card. How many PCIe 3.0 lanes can this use, 16 or 8? I understand, for instance, that running a Crossfire setup will reduce the lanes on my mobo to x8 on each 3.0 slot, but that's also mobo specific. I'm asking if it natively run on 16 or 8 lanes?

I have also read that current games & cards are not enough to saturate 8 PCIe 3.0 lanes anyway, but I am nonetheless curious. Thanks for any answers!

 

[feelinfroggy777]

Natively it will run 16x PCIe lanes if your motherboard can supply it. When running crossfire it will run 8x lanes and if you are running 3 or 4 way crossfire it will even run 4x lanes. For the 580, 8x lanes is plenty of bandwidth and there is little to zero performance loss from running 8x lanes vs 16x.

 

[kanewolf]

The card will negotiate with the motherboard during initialization. So the card will use whatever the motherboard can provide. This is how miners can run 6 cards all with x1 interfaces. The card doesn't care. It is really a question of how many PCIe lanes do you have. If you have a Threadripper CPU and motherboard you have many lanes. If you have a standard desktop, you probably only have 16 available from the CPU.

 

[Math Geek]

you are right that it is motherboard specific. it may have 16 lanes to start with but many boards take away some as you add other stuff. often after so many sata ports are used, the last couple use pcie lanes as does esata and m2 slots. you'll need to check your mobo manual to see how it divides up the lanes and whether your configuration leaves 16 for the card or less.

but as noted above, 4 lanes is likely enough for the card with only minimal performance hit and 8 lanes would likely not be saturated fully at all. in other words, other than just to know, there is really nothing to worry about