Will M.2 SATA SSD Work In A Motherboard M.2 PCIE 3.0 x4?

Question

I need to understand whether or not an M.2 SATA SSD will work in a motherboard M.2 PCI-E 3.0 x4 connector? I recognize I won't get the speed on the SATA SSD that 4 lanes of PCI-E 3.0 can deliver - that's not an issue for me. I'm simply trying to understand if an M.2 SATA SSD can be installed in a motherboard M.2 connector that is configured with 4 PCI-E 3.0 lanes.

I'm trying to understand if I can install two (2) M.2 SATA SSDs in the two M.2 connectors provided on the ASUS PRIME B360M-C-CSM motherboard. I don't care AT ALL about not utilizing the full bandwidth of the PCI-E lanes assigned to each M.2 connector - I only want to install two (2) M.2 SATA SSDs. Here are the specifications for the two (2) M.2 connectors on this ASUS motherboard from the www.asus.com website as of 8/2/2019:

Intel® B360 Chipset : 
1 x M.2 Socket 3, with M Key, type 2242/2260/2280 storage devices support (both SATA & PCI-E mode)
1 x M.2 Socket 3, with M Key, type 2242/2260/2280 storage devices support (x4 PCI-E mode)
6 x SATA 6Gb/s port(s)
Intel® Optane™ Memory Ready

Based on the information provided by Asus, can I install two (2) M.2 SATA SSDs in the two (2) M.2 connectors on this motherboard? I don't want to use any NVME SSDs. BTW, I have a support ticket open with Asus to have them elaborate on their M.2 specs for this motherboard. The tech support people for the motherboard couldn't answer the question. They have escalated my question to product engineering for an answer. However, I would appreciate an answer from this community because Asus tech support clearly doesn't understand the question I'm asking and I'm concerned that they won't be able to understand the answer they get from their product engineering people.

Solution

I'm simply trying to understand if an M.2 SATA SSD can be installed in a motherboard M.2 connector that is configured with 4 PCI-E 3.0 lanes.

Only one of the M.2 connectors is connected to the SATA lane on your motherboard. When an M.2 device is detected in that slot it disables the SATA6G_2 port. The second M.2 slot is specifically designed to work with an M.2 Intel Optane drive.

SATA mode shares with SATA6G_2 port

Source: ASUS PRIME B360M-C-CSM

Based on the information provided by Asus, can I install two (2) M.2 SATA SSDs in the two (2) M.2 connectors on this motherboard?

While the M.2 slot is keyed to accept M slot M.2 devices, a SATA M.2 device, would simply not be detected.