On Thu, Dec 05, 2024 at 04:06:17PM -0500, e...@gmx.us wrote:
To find out if the motherboard imposed any limitations, I checked the
manual. I found these tables, which I can't see the implications of:
M2D_32G M.2 connector
+-------------+---------+---------+---------+---------+---------+---------+
|\ Connector | SATA3_0 | SATA3_1 | SATA3_2 | SATA3_3 | SATA3_4 | SATA3_5 |
+ \----------\+---------+---------+---------+---------+---------+---------+
| Type of SSD | SATA_Express | SATA_Express | - |
Ah, SATA express (SATAe). That's a dead standard that never actually got
implemented in a drive (as far as I know) but was included on
motherboards for some time before it was clear that M.2 won and SATAe
was a dead end. SATAe had the ability to use two SATA ports and an
additonal connector to provide two PCIe lanes for a drive, so a single
connector would have attached to one of the little ports as well as the
two SATA ports beside it. Certain SATA channels on these motherboards
were shared between the SATA ports and the M.2 SATA pins, and PCIe lanes
were shared between some of the M.2 PCIe pins and the SATAe PCIe pins
*and* some of the SATA contollers. The table is trying to explain which
combinations won't work. E.g., if you use a SATA M.2 drive in M2D_32G
you can't also attach a SATA drive to SATA3_3 or a SATAe drive to
SATA3_2/3 (not that such a drive exists), and if use a PCIe x4 SSD in
M2D_32G you can't use SATA3_0/1/2/3, and if you use the SATAe associated
with SATA3_0/1 you drop the speed of M2D_32G to x2 instead of x4.
You can ignore the dark lines because SATAe doesn't exist. If you only
plug SATA disks into SATA3_4/5 you can do anything with the two M.2
connectors. If you want more than two SATA disks you can put an NVMe
drive into M2A_32G and nothing in M2D_32G and use any SATA port.
Or you can use SATA3_0/1 with two NVMe drives but that will drop M2D_32G
NVMe to x2 speed. If you use SATA3_0 you can't put a SATA M.2 drive into
M2A_32G and if you use SATA3_3 you can't put a SATA M.2 drive into
M2D_32G. Simple, right?
:-D
Most desktop motherboards have some sort of limitations/sharing like this because
there are only so many PCIe lanes from the CPU, but they vary in how
well they communicate the information.
