Question NVMe SSD Gen 4 on PCIe 3.0 x8

[hugope]

https://imgur.com/a/3SfUkdJ

View: https://imgur.com/a/3SfUkdJ


The previous picture is from the manual of the motherboard I have. It says I can put a Hyper M.2 X16 card on my motherboard and then I can attach NVMe SSDs to that card. I want to buy a PCIe Gen 4 NVMe SSD x4 and attach it to the PCIe Gen 3 x8 slot, and then add another 2 NVMe SSDs on the x4 slots. My question is, will the NVMe SSD that is in the PCIe Gen 3 x8 slot run as fast as it would, if it was on a PCIe Gen 4 x4 slot?

 

[CountMike]

https://imgur.com/a/3SfUkdJ

View: https://imgur.com/a/3SfUkdJ


The previous picture is from the manual of the motherboard I have. It says I can put a Hyper M.2 X16 card on my motherboard and then I can attach NVMe SSDs to that card. I want to buy a PCIe Gen 4 NVMe SSD x4 and attach it to the PCIe Gen 3 x8 slot, and then add another 2 NVMe SSDs on the x4 slots. My question is, will the NVMe SSD that is in the PCIe Gen 3 x8 slot run as fast as it would, if it was on a PCIe Gen 4 x4 slot?

No, gen3 will be approximately half speed of gen4 even in PCIe gen4 slot. Full NVMe is PCIe x4 of any generation, Two NVMe drives need PCIe x8 adapter of any generation.
So. PCIe x4 gen4 will run at gen3 speed if connected to PCIe gen3 slot, doesn't matter if in dedicated M.2 on the MB slot or PCIe adapter.

 

[Aeacus]

My question is, will the NVMe SSD that is in the PCIe Gen 3 x8 slot run as fast as it would, if it was on a PCIe Gen 4 x4 slot?

No.

While PCI-E 3.0 x8 slot has same bandwidth as PCI-E 4.0 x4, the issue is with M.2 drive itself. All M.2 drives are only x4 (four lane PCI-E), so, using PCI-E 4.0 M.2 drive in PCI-E 3.0 x4 slot, will still have the PCI-E 3.0 x4 speeds.

 

[hugope]

No

No.

Hi, thank you for your answers.

Then, what is the purpose of that feature? Why does it exist? Why does the feature of having a NVMe SSD on a PCIe 3.0 x8 exists?

 

[Aeacus]

Why does the feature of having a NVMe SSD on a PCIe 3.0 x8 exists?

It exists so that people can add more M.2 PCI-E drives to their system, compared to what is otherwise possible.

Normal MoBo has 2x M.2 slots. Some have 1x. Top-end ones can have up to 4x. So, when you have populated all M.2 slots and need more drives to use, you can use the PCI-E add-on card, to add more drives.

 

[Zerk2012]

https://imgur.com/a/3SfUkdJ

View: https://imgur.com/a/3SfUkdJ


The previous picture is from the manual of the motherboard I have. It says I can put a Hyper M.2 X16 card on my motherboard and then I can attach NVMe SSDs to that card. I want to buy a PCIe Gen 4 NVMe SSD x4 and attach it to the PCIe Gen 3 x8 slot, and then add another 2 NVMe SSDs on the x4 slots. My question is, will the NVMe SSD that is in the PCIe Gen 3 x8 slot run as fast as it would, if it was on a PCIe Gen 4 x4 slot?

What motherboard?
Depending on what your using the M.2 drive for you would probably never know the difference unless you were just running benchmarks.

 

[CountMike]

Hi, thank you for your answers.

Then, what is the purpose of that feature? Why does it exist? Why does the feature of having a NVMe SSD on a PCIe 3.0 x8 exists?

PCIe has gone thru several versions, each one doubling the throughput of one before. For all practical purposes, NVMe SDD started with PCIe gen3, now gen4 and gen5 prevail while gen6 is already standardized but not implemented. NVME is protocol for implementation of PCIe on SSD drives connected by M.2 socket format.
Adapters for M.2 sockets to PCIe sockets are generation neutral and could be used forany PCIe generation to any M,2 NVMe SSD. generation, Why x8 ? Because for full throughput of NVMe drive it requires 4 PCIe lanes so adapter has to provide 8 lanes from MB's PCIe bus/slot to feed 2 NVMe drives at full speed.