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Topic: Does the size of PCI express matters on the hashrate of the GPU? (Read 646 times)

member
Activity: 70
Merit: 10
HI Guys

please assist if you don't mind, I'm running two gpu's in my machine, but for some reason the hashrate of the gpu in the second PCIe16 slot is very low?

if tried switching the gpu's but the outcome is the same the gpu in the second PCIe slot performs very poorly.

The well performing gpu run in PCIe x 16 3.0@16 2.0 while the under performer is running in PCIe x 16 3.0@ 4( instead of 16) 1.1.

what must I do to get the hashrate up ( the underperforming gpu currently doing a quarter of what is actually can).

hope some will be able to help.

thank you
member
Activity: 74
Merit: 10
cryptocurrency enthusiast
Thank you all guys!!
full member
Activity: 168
Merit: 100
All CPUs have a limited number of PCIe 'Lanes'
Read more details here:
https://en.wikipedia.org/wiki/PCI_Express#Lane

Lets say a CPU can handle up to 28 lanes
If you plug in one graphics cards directly to the motherboard, it takes 16 lanes.
If you plug the graphics card into a 1x riser, then it only takes 1 lane instead of 16.

This means your CPU will have 27 lanes leftover instead of 12.

Other devices use these lanes as well, like M.2 SSD.

Here is another good explanation.
https://superuser.com/questions/843344/what-is-a-pci-express-lane
newbie
Activity: 30
Merit: 0
No. You want them all at 1x. That way your CPU has more lanes available for more cards.

Why does it have more lanes? Can i plug more riser cable at a same slot?

No that is not what he meant. He meant that each slot on the mother board is connected to CPU. CPU have limited number of slots you can connect to them.

Basically, answer to your question is NO and extra comment given by him does not really concern you.
member
Activity: 74
Merit: 10
cryptocurrency enthusiast
No. You want them all at 1x. That way your CPU has more lanes available for more cards.

Why does it have more lanes? Can i plug more riser cable at a same slot?
full member
Activity: 168
Merit: 100
No. You want them all at 1x. That way your CPU has more lanes available for more cards.
member
Activity: 74
Merit: 10
cryptocurrency enthusiast
If I use a riser cable to conect my GPUs on the motherboard, the size of the slot will matter? 1X or 16X?
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