[SOLVED] PCIe gen3x4 on PCIe gen 3x2 Port

[DavidISP]

Hello guys, i wan't your help about this.
I have 2 question,

1. Any body here had trying to use SSD with PCIe gen 3x4 on PCIe gen 3x2 port?
2. What happens after that?

Thank you for give me your experience

 

[Joakim Agren]

Hello guys, i wan't your help about this.
I have 2 question,

1. Any body here had trying to use SSD with PCIe gen 3x4 on PCIe gen 3x2 port?
2. What happens after that?

Thank you for give me your experience

Are you planning to use a PCI Express expansion bracket card to install NVME drives on? If so a Gen 3 X4 port will have a total of 4 lanes and X 2 just 2 lanes available bandwidth. Each lane is 1GB/s in each direction so a X2 means a max of 2GB/s per direction. Some NVME drives is above that limit so you will be limiting the capacity of the drive but it will work. On the X4 port you will have a max of 4GB/s and that is enough to be used with even the fastest NVME PCI Express gen 3 drives on the market today. But many of those expansion brackets have room for 2 NVME drives so if you want o use both of them at full capacity you must use a X8 or X16 port.

 

[DavidISP]

Are you planning to use a PCI Express expansion bracket card to install NVME drives on? If so a Gen 3 X4 port will have a total of 4 lanes and X 2 just 2 lanes available bandwidth. Each lane is 1GB/s in each direction so a X2 means a max of 2GB/s per direction. Some NVME drives is above that limit so you will be limiting the capacity of the drive but it will work. On the X4 port you will have a max of 4GB/s and that is enough to be used with even the fastest NVME PCI Express gen 3 drives on the market today. But many of those expansion brackets have room for 2 NVME drives so if you want o use both of them at full capacity you must use a X8 or X16 port.

Yes, i have plan to use SSD NVME on slot M.2 PCIe gen 3 interface. So, SSDs with PCIe gen 3 x4lane interface can be used well on PCIe gen 3 x2lane port interface and it's just that the speed that will get only 2Gb/s or can only use 2lane only?

 

[Joakim Agren]

Yes, i have plan to use SSD NVME on slot M.2 PCIe gen 3 interface. So, SSDs with PCIe gen 3 x4lane interface can be used well on PCIe gen 3 x2lane port interface and it's just that the speed that will get only 2Gb/s or can only use 2lane only?

Yes X4 stuff is backwards compatible with X2 slots but as I said they will run at half speed. If you put a NVME drive in a X2 slot then you will only be able to run 1 drive max and the max speed from the drive will probably be around 1.8 GB per second. So you will be able to run a Intel 660P drive on there at full speed but not the faster Samsung 970 EVO drive that requires over 3GB/s for full sequential reads and writes. On a X4 slot you can run even the 970 EVO at Max speed since it tops out at about 3.2GB/s. But once again you will not be able to run 2 such drives even on a X4 slot. For that you must use a X8 or X16 slot.

 

[DavidISP]

Thank you very much Joakim Agren for your explaination about PCIe gen interface