Review on Ableconn PEXM2-130 Dual PCIe NVMe M.2 SSDs Carrier Adapter Card (ASMedia ASM2824 Switch) - High-Speed 2X M.2 NGFF PCIe NVMe SSD Support for Mac & PC (PCIe x8, Non-Bifurcation Motherboard) by Heather Green

This card isn't cheap, but it solves a specific problem - old chipsets/boards that don't have many PCIe lanes. I have a Maximus Hero VII running at 4790K @ 4.8 and I don't need to update my platform yet. I've already populated the slots with 1080 TI (x16), USB 3.0 card (x1), sound card (x1) and network adapter (x1) as well as an existing x4 PCIe NVMe adapter. I wanted to add another drive so I took another x4 adapter and put it in the bottom x4 slot. Unfortunately I don't have enough strips and if you put something in the bottom black slot all the x1 slots will be cut off! Enter this card. I put both NVMe drives in the adapter and put it in an additional x16/x8 slot (where the x4 card used to be). The black x4 is empty, so the x1 slots are enabled. Everything booted up correctly, both SSDs run at full x4 speed (3000+ reads, almost write speed) and no drivers were installed. I haven't run a test to see if there's a problem loading both drives at the same time, but I don't plan on doing it anyway. Again, this isn't a cheap card, but it solved a problem I would have otherwise had to buy a single larger SSD or upgrade my system. Recommended as long as it lasts.