NVMe questions

so I haven't bought a notebook for 2 years and feel a bit oudated.
I've seen so many m.2 standards that I don't know how they work. I've read that NVMe is the new thing that delivers great speeds. but how to know if a notebook has NVMe? if it has an m.2 slot does it mean that a NVMe SSD will work on it at lower speeds even if the notebook doesn't support it?
what are the cheapest notebooks with NVMe?
what's the difference betweem a M.2 PCI-E SSD and a M.2 NVMe SSD?
and what about all the sizes?
I'm really confused. can someone explain it to me? tkx.

 

It is confusing indeed. I don't know everything about it either, I just know that there are SATA M.2s, PCIe M.2s and both. Most likely the later (both) are referred as NVMe. Do note that as the drives, there are also machines that support either, but not both, so the confusion is even greater.

 

NVMe is an extension to the m.2 PCIe SSD format and enables the current fastest speeds for SSDs. The BIOS needs to specifically support NVMe though for that to work. And the PCI slot needs to be x4 speed.

 

NVMe is just a format used for M.2 slots that can support it. Not all M.2 slots can, but all NVMe drives for the time being use M.2. Some use a PCIe adapter for desktops, but since this is a notebook forum, you'll only find NVMe drives compatible with the M.2 slot.

The x4 isn't REQUIRED to run it, but it is required to get full speed. You can run two of them in x2 M.2 lanes, but you won't get the full benefit of NVMe speeds. The SATA M.2 ones use AHCI, which is an aging tech, though still proficient for the general consumer.

Just to be clear, you can't just put an NVMe drive in any M.2 slot, even if it fits. The BIOS has to be able to communicate with an NVMe drive, and not all bios's can, especially older machines that utilize the M.2 slot as sata or wifi only.