And I’m wondering whether I should get Gen4 or Gen5 variant. My host is based on WRX80 platform so I have Gen4 x16 connection to host but I wonder if getting Gen5 card like this would allow me to use Gen5 drives at full speed?
My intended use is to make:
6x M.2 RAID10 + 2x M.2 RAID1
But those 2 won’t be used simultaneously most likely so it would be beneficial if that RAID1 could use 2x Gen5 NVME drives and utilize full Gen4 x16 bandwidth (which is the same as Gen5 x8)
And second question - does anyone know if those cards support IOMMU? Currently I use OWC M.2 Shuttle enclosure which has Gen3 PLX switch and it does fully support IOMMU so I can pass through two drives to one VM and another two drives to another one. I’d like to do the same with this card - use RAID10 as host storage for VMs and that RAID1 passed through to one of VMs. Anyone used something like this?
If I were to get Gen4 card I’d probably take Sonnet Silent one, if Gen5 then Areca one.
It should run at the max that gen 4.0 x8 can do. So you should get the bandwidth of a single Gen 5 x4 ssd. As long as you are using a gen 5 plx on a gen 4 board.
The drives will connect at full speed to the plx switch, but the plx will connect to cpu at whatever the mobo slot is. So if you get a x16 card in a x16 pcie 4.0 slot, you have like a x8 pcie 5.0 worth of bandwidth between the plx card and the cpu.
So yeah you can have some ssds go faster but if you use too many at the same time it will bottleneck.
Since both are reputable manufacturers with customer support staff, maybe you can try asking them as well.
There are plx gen4 and gen5 on aliexpress too, probably cheaper. Although they are still in the 300 to 650 bucks range so not really that cheap in absolute terms.
It seems the other one is based off a pcie 3.0 card with a different plx chipset, and while it has the same little connector for auxiliary power it does not come with the same cable adapter as the pcie 3.0 one here ( see last picture, also yes they lie and say this is pcie 4.0 while the plx chip they are using is pcie 3.0) https://it.aliexpress.com/item/1005011819289562.html
The pcie 4.0 ones claim to use this broacomm plx chipset, that is actually pcie 4.0
As usual this is aliexpress so it may or may not be true.
It would indeed be good to verify with customer support, cause there’s a lot of misconception around these. There are also “dumb” switches out there that don’t take the generation into account and just switch lanes.
