Asus Prime Z370-A actually offers 3 options for mounting PCIEx16 card?!?

[Mortis Angelus]

Hello,

 

I just want to confirm that I have actually interpreted this correctly:

 

 

Is it really true, that I could plug the GPU into any of the x16 slots of the Asus Prime Z370-A (right image) and get full x16 speeds from any of those slots? I want to double check this with you guys, because e.g. the Aorus Gaming 5 (left image) and most other motherboards (including top of the line boards like Asus Maximus Formula) seem to offer this.

 

Then again, on the next page, they show this table:

:

 

That one indicates I can't even use a single GPU in the second slot only. Why do they do this (if it is true)?

 

Also, why is the third slot not even mentioned?

 

And if you wonder why I ask, I want to use a riser cable to make the GPU stand in the case, but I don't want to block off all the mobo with the cable. I will also be using the Creative AE-5 soundcard, and that one I'd prefer to mount lower, but the riser cable can't reach around the card to reach the top slot.

 

[W-L]

Just now, Mortis Angelus said:

-SNIP-

You should be using the top slot, they are all full sized x16 PCI-E slots but only the top is wired up for full X16 speed, the second and third full size PCI-E slots are both wired for X8 speeds. In general though you won't saturate a PCI-E 3.0 X16 slot with a GPU.

[Mortis Angelus]

8 minutes ago, W-L said:

You should be using the top slot, they are all full sized x16 PCI-E slots but only the top is wired up for full X16 speed, the second and third full size PCI-E slots are both wired for X8 speeds. In general though you won't saturate a PCI-E 3.0 X16 slot with a GPU.

Thanks for the reply!

 

Yeah, from what I've read, not even a 1080Ti will max-out a PCI3x8 slot.

 

But why does the table say "N/A" for second slots?

[porina]

The Z370 platform supports CPU lane configurations of 16x only, 8x + 8x, or 8x + 4x + 4x. I wonder if they did that with the 3rd long slot on the bottom, or if that might be connected to chipset lanes not CPU lanes. I had a quick scan of the manual but it didn't offer any clues. 

 

I'm 99% confident you can plug the GPU in the 2nd slot and run it at 8x no problem. I really don't know what they're doing with the 3rd slot.

 

3 minutes ago, Mortis Angelus said:

But why does the table say "N/A" for second slots?

The CPU only has 16 lanes. If you are already using 16 lanes on the 1st slot, there's none left for the 2nd slot.

[W-L]

7 minutes ago, Mortis Angelus said:

Thanks for the reply!

 

Yeah, from what I've read, not even a 1080Ti will max-out a PCI3x8 slot.

 

But why does the table say "N/A" for second slots?

As mentioned if your running only a single GPU it will be in full X16 mode and the second slot will not be utilized, for dual GPU's it splitting it between the two so each card gets X8, X8 speeds.