16 lane PCIe CPU with 4GPU in PLX motherboard a bad idea? Tweet

[volatilecycle]

Hi,

I'm trying to work out what motherboard to get for the new i9 9900K CPU (16 lane PCIe).

I've seen this Asus WS Z390 Pro...
https://edgeup.asus.com/2018/z390-mothe ... e/5/#wspro

It says it has PLX chips to support 4GPUs at x8/x8/x8/x8

Sounds great, but is it actually something that would work ok with Octane?
It can't really get 32 lanes out of a 16 lane CPU so don't know if it would affect performance too much.

Would a normal 2 GPU motherboard be better with this CPU so they both run at x8 speed?


Hope you can help,
Richie

[zoppo]

PCIe lanes don't matter. I was shocked too:

https://www.pugetsystems.com/labs/artic ... Conclusion

[pegot]

It was my understanding that faster PCIe lanes assisted in geometry loading, which becomes especially important for animations. But I think it has been stated many times in the forums here that lane speed has little to no benefit for rendering once the geometry is already loaded.

There was a pretty detailed thread a few years ago where a bunch of users compared loading speeds and different card configurations. Don't remember what the overal consensus was. Maybe a little less critical now with V4's improved loading optimizations?

One thing I would like to see more data on certinly is if boards with PLX chips are beneficial to Octane?

[BorisGoreta]

You can only feel loading speeds when PCI lanes are at x1 speed and when the scene is bigger.

[jblessing]

Just a heads up, some people has had issues with PLX and win 10 with multiple GPUs...look around this and other forums for more info.

[paride4331]

HI guys,
https://render.otoy.com/forum/viewtopic.php?f=9&t=67801&p=348427#p344997
Regards
paride

[volatilecycle]

Thank you for your replies everyone.

When I first read that thread, I thought it was just an issue with the Asus WS X99 motherboard. But maybe you are right and these issues would also happen with the Asus WS Z390 Pro. Hard to know without buying it

It's tricky building a PC.