Just curious… If you have a PCI-E adapter that support 2, 3, or 4 m.2 slots, do you still have to have a mobo that supports the x4 by 4 slot config? If not, will it mount 4 NVMe drives in separately in Windows or as all one drive? Maybe not mount the drives at all? Trying to make sure that before I invest in a setup I can pipe as many NVMe drives to the CPU as possible.
Thanks for the feedback!
Unless it is a raid controller too they should not show up as one drive.
Though I have no experience with this at all.
In my experience the adapter will pass the drive straight through to the OS, even if the MB does not natively support M.2.
Bear in mind how many drives you want on the adapter, compared to how many it is wired for, I.E. an adapter wired at pixie x4 with 2 sockets may limit each socket to 2 lanes of pice.
This is still faster than SATA, but if you want 4 drives, make sure the card is wired at 16x, or it will be bottlenecked
There are two main types of PCIe add-in-card -> M.2 adapters:
“Dumb” ones, that only route what lanes are available to 1 or more M.2 drives. If only x8 is available from the slot, you can only use 2 M.2 slots on the adapter even if it has more than that. If the slot is only x4, only 1 M.2 is usable.
Adapters with a PLX chip that take what lanes are available and use a switch to distribute the bandwidth to multiple M.2 devices. In this case, no matter what the number of lanes from the slot is, you can use all the M.2 slots.
If you have a “dumb” adapter, motherboard support for bifurcation (either x16 to x4/x4/x4/x4 or x8 to x4/x4) is absolutely needed. Compatibility will be better (but not guaranteed) for adapters with a PLX.
In either case, the drives will show as individual drives, unless you enable NVMe RAID, in which case each set will appear as a single drive. (NVMe RAID will require a BIOS (&AGESA) update and rebuilding all existing (SATA) RAID volumes on AMD Ryzen Threadripper platform. Support on regular Ryzen hasn’t been announced. On Intel X299, you will need a (yet unreleased) ROC key.)
I figured as much… Just brewing on the idea of mounting both of my NVMe drives on a card instead of on the mobo. Not looking for raid at this point. (Yet.) I was having the same thoughts as you about how the cards work, however, if your comments are accurate then the Asus HyperX card is a “dumb card”? I believe it requires the bifurcation on the mobo. For $100 I would think it would be more than that. As to your comment about the ROC key, That really only matters with VROC or bootable raid correct? You can still build a software raid within Windows correct?
HyperX is Kingston, not Asus. 
The Asus one is plain “Hyper”.
The only Asus Hyper M.2 adapter I could find is just one M.2 drive to x4 slot, so it would never need any smart logic, anyways.
By “ROC”, I meant VROC. Sorry about the confusion.
You can use Windows volumes if you don’t need to boot off the volume, but having Windows boot off an NVMe is one of the best uses for such a drive.
I feel that the added bandwidth of multiple NVMe drives really comes to its own if you do things like raw and/or 4K video editing. Otherwise even though the benchmark numbers are impressive, the actual benefit in everyday use is a lot less, and having RAID 0 you increase the risk of losing all your data.
See below.
This is the one I was referring to. I knew what you were getting to with the ROC comment. I am with you on the performance. I don’t need all of that HP. Just looking to keep all of my m.2 cards in one spot.
Doesn’t say anything about switching or PLX, so I gather it just routes the x16 lanes direct to x4/x4/x4/x4 M.2 slots. PLX is such an expensive component and increases the compatibility, so it would surely be mentioned (never mind that a PLX chips are at least in the ~$100+ range, so no way would the adapter card be sold for $100).
It’s actively cooled with a very small (~20 - 30 mm) fan, so noise may become a problem. Luckily there is a fan switch, so you can turn it off, if your chassis temperatures aren’t bad. (Found the product info on Asus’s page: https://www.asus.com/Motherboard-Accessory/HYPER-M-2-X16-CARD/overview/)