A motherboard’s model will determine how many M.2 slots will be included, where they will be situated, and whether or not they include a cover or heatsink. Keep in mind that PCIe lanes are laid out in a doubling sequence (1, 2, 4, 8, 16), so if you occupy four lanes from an x16 slot, it will not downgrade to an x12. This is useful for those who wish to add additional GPUs to their build, or to add a PCIe slot on a smaller form-factor motherboard; which typically only has one. Benefits of Using an M.2 PCIe Adapter

PCIe Adapters for NVMe or PCIe SSDs in 2023 Best M.2 PCIe Adapters for NVMe or PCIe SSDs in 2023

The data interface is handled by a PCIe to PCI bridge chip. This part is not a problem, PCIe to PCI bridge chips are used on many motherboards and expansion cards and they work just fine. A very good budget M.2 PCIe Adapter that supports M-Key PCI-E NVMe and AHCI SSD up to M.2 2280 form factor. The M.2 PCI-E adapter comes with an aluminum heatsink that keeps the SSD cool and prevents it from overheating. It can support a dual-sided SSD module having a 1.5mm component height on the top and bottom side and is compatible with major operating systems that include Windows, Mac, and Linux.

Yes here are a couple that are specifically made for running PCIe4 M.2 Drives. Here’re the ones I can think of right now:

PCI to USB converter/adaptor [SOLVED] Possible to get a PCI to USB converter/adaptor

A Redundant Array of Inexpensive Disks (RAID) can be made – or complemented – with the use of an M.2 PCIe adapter; depending on what configuration you wish to use. Of course, there are two sides to every coin, and such is the case when it comes to occupying PCI Express slots, and their accompanying CPU PCIe lanes – or obstructing other components.

The ever-increasing need for digital storage has made the limited connectivity provided by PC hardware manufacturers all the more pronounced. Then there is power. PCI slots need 5V but PCIe slots don't provide it, so you end up with a cable hanging off the adapter board that needs to be connected to the power supply. By using the PCIe slot, you then begin taking advantage of your CPU’s PCIe lanes, which are otherwise untapped. (You’ll have to utilize a PCIe-Slot that is hooked up to the CPU, usually the two topmost PCIe-Slots) Yes it’ll work. You have a second pcie slot free which is fast enough for this add-in card. You might even have the top pcie slot free as well, depending on if you have a graphics card installed or are using the igpu.

PCIe Adapters in 2022 - Tech Junkie The 5 Best M.2 PCIe Adapters in 2022 - Tech Junkie

Unfortunately most computer motherboard manufacturers seem to want to follow the rush twords new technology even when older technology still works fine. What i don't understand is why do computer motherboard manufactures even put PCI-e x1 card slots in their systems. At the moment, the only technology that uses PCI-e slots is either graphics cards, raid controllers, or USB2.0. As far as graphics cards go, the PCI-e x16 slot is a necessary advancement. However, no one buys raid controllers because most people who use it have raid chips inside their motherboards anyways, this goes the same with USB2.0.If you are like one of many people who have only used their motherboard’s PCIe slots to plug in a GPU, then you will find great utility from an M.2 PCIe adapter. Especially because the motherboard’s chipset has a limited amount of PCIe lanes it can access. Also note, that M.2 PCIe adapters are interposers that adapt to the mechanical interface in which they are applied.