PCIe 4.0 x4 to PCIe 3.0 x8 Switch?

[NablaSquaredG]

As far as I can tell from the datasheets, it should be possible to build a device that splits / switches PCIe 4.0 x4 to PCIe 3.0 x8.

I have a couple of machines where such a device would come in very handy (i.e. splitting a PCIe 4.0 M.2 Slot into an PCIe 3.0 x8 Slot for a NIC / HBA)

Does such a device exist yet? I couldn't find anything...

 

[cesmith9999]

probably not

if it did, the cost would be too much and have too little in inventory to make a device profitable.


Chris

 

[NablaSquaredG]

I guess a full PCIe 4.0 HBA with 8i outputs would also do the job... But I also haven't been able to find one either

 

[EffrafaxOfWug]

As cesmith says, it's technically possible but would be of too little utility to be popular I think; you'd need a very expensive PCIe switch/controller to change from one to the other.

As for the PCIe 4.0 HBA, they do exist - the LSI/Broadcom 9500-8i for example, although it needs some relatively exotic cables.