I've not seen anyone talk about these rather interesting if niche PCIe cards so this is my experience with one so far. I have an Asrock mini-ITX motherboard in a Jonsbo N3, 8 bay NAS case and the motherboard only has 4 native SATA ports so I've been looking for ways to add more so I can use all 8 bays.
My first experiment was by replacing the unused wifi M.2 A+E card with a dual port SATA card with a JMB582 chipset. This worked well but only gave me 2 extra ports and was generally a bit shonky to look at. The drawbacks to this were that the wifi M.2 slot is right next to the only pcie slot on the motherboard and the SATA sockets pointed directly at it. Even by searching my massive bucket of SATA cables I couldn't find a cable with a plug short enough so the M.2 pcie card was leaning over at an 95 degree angle and the SATA cables were bent round at right angles and rubbing against all the solder joints on my Solarflare SFN8522 card. Both SATA ports faced the same direction so right angled SATA connectors would not fit either. Not ideal but it worked. Bandwidth limited to pcie 3.0 x1 and only 2 ports though.
Second experiment was again with an M.2 A+E card but this one had a ribbon cable leading to a 4 port daughter card with an ASM1064 chip. SATA sockets were accessible and easy to use. Drawback, the ribbon cable is completely unshielded so when I ran `hdparm -tT /dev/sdX` against an SSD attached to it, I got 40MB/s (not a typo). Too much electromagnetic smog inside a very crowded mini-ITX case! Removing it and wrapping a couple of layers of aluminium kitchen foil round the ribbon cable (steering clear of the connector ends) and then with non-conductive tape and retesting got it up to about 100MB/s. Still crap but better and proof that it's the unshielded cable at fault. Also, due to some weirdness in the linux ahci driver, it finds 24 SATA ports on this card and tries to talk to them all at boot time. That one went back due to the unshielded cable.
Third and final attempt was using a half height PCIe riser card that requires PCIe bifurcation. There seem to be a lot of these around on Amazon though I've not managed to find the correct search arguments to find only these but this https://www.amazon.co.uk/dp/B0GRWYBRD2 is the one I got. This is a half height PCIe x16 card with an M.2 socket on each side and an x16 PCIe socket on the top that runs at x8. I've switched the bracket on my Solarflare card over for a low profile one and that's inserted into the top x16 slot then I have a 5 port JMB585 (PCIe x2) M.2 to SATA adapter (£17) on one side and a Samsung PM9A1a on the other. BIOS is set to use x8x4x4 bifurcation. I've got all 8 bays usable and still have one spare SATA port left over for luck. I've got a dual port 10GbE card and 3 M.2 SSDs all running at full speed. Only drawback I've found so far is that the SF-109041 bracket that I bought to convert the SFN8522 to low profile is wrong handed so the screwhole on the bracket is on the wrong side to fit in the hole. Google tells me that's normal but it still seems odd. Oh, and any M.2 heatsink needs to be pretty much exactly 22mm wide or it'll short out the wires leading to the upper pcie socket.
My first experiment was by replacing the unused wifi M.2 A+E card with a dual port SATA card with a JMB582 chipset. This worked well but only gave me 2 extra ports and was generally a bit shonky to look at. The drawbacks to this were that the wifi M.2 slot is right next to the only pcie slot on the motherboard and the SATA sockets pointed directly at it. Even by searching my massive bucket of SATA cables I couldn't find a cable with a plug short enough so the M.2 pcie card was leaning over at an 95 degree angle and the SATA cables were bent round at right angles and rubbing against all the solder joints on my Solarflare SFN8522 card. Both SATA ports faced the same direction so right angled SATA connectors would not fit either. Not ideal but it worked. Bandwidth limited to pcie 3.0 x1 and only 2 ports though.
Second experiment was again with an M.2 A+E card but this one had a ribbon cable leading to a 4 port daughter card with an ASM1064 chip. SATA sockets were accessible and easy to use. Drawback, the ribbon cable is completely unshielded so when I ran `hdparm -tT /dev/sdX` against an SSD attached to it, I got 40MB/s (not a typo). Too much electromagnetic smog inside a very crowded mini-ITX case! Removing it and wrapping a couple of layers of aluminium kitchen foil round the ribbon cable (steering clear of the connector ends) and then with non-conductive tape and retesting got it up to about 100MB/s. Still crap but better and proof that it's the unshielded cable at fault. Also, due to some weirdness in the linux ahci driver, it finds 24 SATA ports on this card and tries to talk to them all at boot time. That one went back due to the unshielded cable.
Third and final attempt was using a half height PCIe riser card that requires PCIe bifurcation. There seem to be a lot of these around on Amazon though I've not managed to find the correct search arguments to find only these but this https://www.amazon.co.uk/dp/B0GRWYBRD2 is the one I got. This is a half height PCIe x16 card with an M.2 socket on each side and an x16 PCIe socket on the top that runs at x8. I've switched the bracket on my Solarflare card over for a low profile one and that's inserted into the top x16 slot then I have a 5 port JMB585 (PCIe x2) M.2 to SATA adapter (£17) on one side and a Samsung PM9A1a on the other. BIOS is set to use x8x4x4 bifurcation. I've got all 8 bays usable and still have one spare SATA port left over for luck. I've got a dual port 10GbE card and 3 M.2 SSDs all running at full speed. Only drawback I've found so far is that the SF-109041 bracket that I bought to convert the SFN8522 to low profile is wrong handed so the screwhole on the bracket is on the wrong side to fit in the hole. Google tells me that's normal but it still seems odd. Oh, and any M.2 heatsink needs to be pretty much exactly 22mm wide or it'll short out the wires leading to the upper pcie socket.
