Motherboard pcie lane configuration

[bigdog1565]

I just want to double check my facts here but if I use duel gpu on a Asus ROG STRIX B450-F GAMING ATX AM4 Motherboard. Would it go from pcie x16 to x8/x8?

[WereCat]

yes 

[Haro]

That board does not have pcie switchers iirc and does not support sli. 

Either way if you're gaming it's dead and is a waste of money and does not scale well and brings little to no performance benifits. 

[VeganJoy]

both would be at x8, which may not be that much of an issue for you. keep in mind that the 2080ti can barely saturate x8 lanes as it is, so for lesser gpus you won't see much of a performance drop

[VeganJoy]

1 minute ago, TofuHaroto said:

That board does not have pcie switchers iirc and does not support sli. 

Either way if you're gaming it's dead and is a waste of money and does not scale well and brings little to no performance benifits. 

you can use crossfire though, right?

[Haro]

Just now, VeganJoy said:

you can use crossfire though, right?

It would be through the chipset afaik (at least with this board) if I remember the lanes configuration, but that wouldn't be a nice experience..

[svmlegacy]

5 minutes ago, bigdog1565 said:

I just want to double check my facts here but if I use duel gpu on a Asus ROG STRIX B450-F GAMING ATX AM4 Motherboard. Would it go from pcie x16 to x8/x8?

According to the manual (https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM4/ROG_STRIX_B450_F_GAMING/E14401_ROG_STRIX_B450-F_GAMING_UM_WEB.pdf)

 

AMD Ryzen™ 2nd Generation/Ryzen™ 1st Generation Processors

2 x PCIe 3.0 x 16 SafeSlots (support x16, x8/x4 modes)

AMD Ryzen™ with Radeon™ Vega Graphics

1 x PCIe 3.0 x 16 SafeSlot (supports x8 mode)

AMD® B450 chipset

1 x PCIe 2.0 x 16 slot (max. at x4 mode)*3 x PCIe 2.0 x 1 slots

*PCIe x16_3 slot shares bandwidth with PCIe x1_2 and PCIe x1_3.

 

So as long as you have a non-APU chip, it will run in x8/x4 if you use both PCIeX16_1 & PCIeX16_2.

 

PCIeX16_3 is provided by the chipset, and is maximum x4 2.0 if PCIe x1_2 and PCIe x1_3 are unpopulated.

[JoostinOnline]

1 hour ago, bigdog1565 said:

I just want to double check my facts here but if I use duel gpu on a Asus ROG STRIX B450-F GAMING ATX AM4 Motherboard. Would it go from pcie x16 to x8/x8?

It should, but there's also no reason to do a dual GPU setup.  SLI and Crossfire are dead.   In the vast majority of games you'll end up just using one GPU.  In the games that do support it, you'll run into all kinds of problems, like microstutters.

[bigdog1565]

@svmlegacy so i would presume this would be the same principle according to your advice and the manual if I was going to use duel nvidia gpus in non-sli

[bigdog1565]

@JoostinOnline I am not planning to use duel gpu for gaming

[svmlegacy]

3 hours ago, bigdog1565 said:

@svmlegacy so i would presume this would be the same principle according to your advice and the manual if I was going to use duel nvidia gpus in non-sli

Yes. This actually goes for any device inserted into the PCIe slots.

[JoostinOnline]

7 hours ago, bigdog1565 said:

@JoostinOnline I am not planning to use duel gpu for gaming

What for then?

[bigdog1565]

@JoostinOnline Mainly for AI

[JoostinOnline]

5 hours ago, bigdog1565 said:

@JoostinOnline Mainly for AI

Sorry, I should have been been more clear about what I was asking. Are you hooking up cards via Crossfire, SLI, or NVLink? Are they Quadro cards?

[bigdog1565]

@JoostinOnline na don't worry i did not explain it well in my question. I am not planning to link my gpus in sli or crossfire

[JoostinOnline]

21 minutes ago, bigdog1565 said:

@JoostinOnline na don't worry i did not explain it well in my question. I am not planning to link my gpus in sli or crossfire

In that case, 8x PCIe 3.0 is fine.