[SOLVED] PCIe 4 and multiple GPUs

[drlloyd2]

My old AM4 motherboard went POP last week and I've ordered a ROG Crosshair VIII Dark Hero as a replacement. In my old system I ran a 1080ti for my main QHD monitor and VR headset but at some point dropped in a spare 1050ti and plugged a cheap TV into it which I used mostly to show videos while working/gaming on the main screen. At the time I really didn't think about the possibility the 2nd card would compete for bandwidth with the 1080.

In the new system the 1080ti is going to have to stay for now since there's no good upgrade path given current price/availability craziness. I probably won't leave the VR plugged into the 1080ti's other output, freeing it up for connection to the TV if I want to run it all from a single card.

With this motherboard, is the presence of a second, slower card going to hamper the 1080 by eating up its bandwidth? Is there any way it can be configured not to do so?

 

[Newtonius]

If you're just watching videos with the 1050 Ti, it's not really using up much bandwidth. If you are seeing chugging due to bandwidth overcap, you can set up bifurcation in your motherboard's BIOS. This evenly splits the data per PCIe bus from a 16-8 to an 8-8 array splitting the data from one bus into two evenly.

 

[drlloyd2]

If you're just watching videos with the 1050 Ti, it's not really using up much bandwidth. If you are seeing chugging due to bandwidth overcap, you can set up bifurcation in your motherboard's BIOS. This evenly splits the data per PCIe bus from a 16-8 to an 8-8 array splitting the data from one bus into two evenly.

I'm not really worried about the 1050 not getting enough bandwidth, but the other way around - the 1050's presence forcing the 8/8 to limit the 1080's performance.

 

[mdd1963]

Any AM2 CPU is already limiting a 1080Ti's performance more so than a PCI-e x 8 vs. 16 ever would...

(You could always test performance with the 1050 installed and then removed for yourself to be sure)

 

[drlloyd2]

Any AM2 CPU is already limiting a 1080Ti's performance more so than a PCI-e x 8 vs. 16 ever would...

(You could always test performance with the 1050 installed and then removed for yourself to be sure)

Sorry, AM2 was a typo - it's AM4 and the new board will be getting a recent-vintage Ryzen 7 5800x.

 

[hotaru.hino]

Considering that the maximum bandwidth both will get is PCIe 3.0 x8, and given that an RTX 2080 Ti doesn't really any practical performance loss on PCIe 3.0 x8, you'll be fine.

 

[Newtonius]

I'm not really worried about the 1050 not getting enough bandwidth, but the other way around - the 1050's presence forcing the 8/8 to limit the 1080's performance.

Shouldn't be a problem, that board, CPU, and PCIe 3.0 (not even 4.0) will be enough to handle both cards without bottle-necking. Video playback takes way less data than gaming, so you'll be fine. It should be able to handle even more if anything.