Install HWiNFO64 and look at Bus >Intel® Skylake – PCI Express Root Port specs (as that is what you will have, as that is the cpu of your E5-575) of your PCI (see below) as that will give you an indication of your M.2 type specs. I've also included the suitable and recommended E5-575/E5-575G Acer suggested M.2 drives.

E5-575/E5-575G Acer suggested M.2 drives.

Have a look at all 4x PCI Root Pots and see their overall versions and speeds, as I've also given you the official Acer Service Guide suggested M.2 drives for your E5-575 laptop. As some suggest that both will work which is M.2 SATA III 6GB/s B&M End Key type or the PCIe's 3 xx that ???should work??? and are backward compatible but, some are not, so be careful! as the plain M.2 SATA III 6GB/s M.2s are the safest for this laptop but and what HWiNFO64 is showing PCIe 3 x4 (which is very unusual???) is there, that is why check all 4x and see, as. buying a PCIe 3 x4 M.2 drive could be limited to SATA3 speeds in this laptop.

Yes, your laptops PCI takes an M.2 PCIe 3 x1 at Max Link Speed of 8GT/s, that slot that your laptop has, was made for the Intel DC P4511 1TB Internal M.2 PCIe NVMe SSD 22110 M.2 NVMe PCIe 3.1 x4 SSDPELKX010T801 type drives (see caption below as the Intel has the same 4x pins and matching other pins) so buy those types of drives as they will work. Also look at this HP "HP EX900 M.2 1TB, Internal 5XM46AA#ABC Solid State Drive"

Intel DC P4511 1TB Internal M.2 PCIe NVMe SSD 22110 M.2 NVMe PCIe 3.1 x4 SSDPELKX010T801