nvme 4.0 when used in conjunction with GPU needing 3.0 riser cable.

Enjin

n00b
Joined
May 30, 2013
Messages
9
Im building a new computer in a SFF case and in doing so I will be utilizing a gpu riser cable (pcie 3.0). What I am not sure about is if I do this and configure it accordingly in the bios, will that limit all other PCIE to 3.0 as well? So the root of my question is this, since I will be using a pcie 3.0 riser cable, is it pointless for me to search for a nvme 4.0 ssd?

CPU: 5600x
Mobo: Strix B550-I Gaming
GPU: RTX 3080 (with riser cable)

Thanks
 

thesmokingman

Supreme [H]ardness
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Nov 22, 2008
Messages
6,617
Technically if there are no redrivers used in the cable then it shouldn't make a difference, putting aside electrical losses.
 

GotNoRice

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Jul 11, 2001
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PCIe 4.0 has tighter tolerances than PCIe 3.0 but the slots use the same number of pins and there is no official spec for riser cables either way. Most of the riser cables that say PCIe 3.0 probably only say that because that was the fastest spec out when they were made, not necessarily because they wouldn't work at PCIe 4.0 speeds. If it's a PCIe 4.0 slot and a PCIe 4.0 card, the riser cable won't block that unless it's so long that the signal degrades or acts like an antenna picking up too much interference from other components.
 

Enjin

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May 30, 2013
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Lets say for certain, I will be using it as a 3.0 cable (I dont know, but assuming worst case scenario). I just dont know if the speed of the ssd drive is tied to the the speed of the gpu. I dont know if you can configure one as 3.0 (gpu) and one as 4.0 (drive)
 

TheSlySyl

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May 30, 2018
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I'm not using a riser cable, but my GPU is on PCI-E 3.0 and my 4.0 NVME is on PCI-E 4.0 (my other 3, 3.0 NVMEs are also on PCI-E 3.0).

It was all automatic.
 

GotNoRice

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Lets say for certain, I will be using it as a 3.0 cable (I dont know, but assuming worst case scenario). I just dont know if the speed of the ssd drive is tied to the the speed of the gpu. I dont know if you can configure one as 3.0 (gpu) and one as 4.0 (drive)

I really don't think that you will have to configure anything. If the card has to fall back to a lower PCIe version for whatever reason, it should do so automatically, and only for that one slot. Just like using a PCIe 2.0 sound card wouldn't stop your GPU from running at 3.0 or 4.0 speeds.
 

Enjin

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May 30, 2013
Messages
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I had heard that there were a lot of issues with gen 4 GPU's being used with gen 3 risers in gen 4 slots. And from my understanding using gen 4 for GPU's is basically pointless, I figure I may as well just set the gpu slot to gen 3 and not worry about it. I just did not know if its one setting that affects both. But it sounds like according tothe slysly, that would be a no.
 
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