Adding a second M.2

[email protected]

Active member
I have a Desktop with a Strix Z270E mb. I am going to add a second M2 drive in the second M2 slot.

Confused re various things I have read, Do I need to make BIOS changes before I can format and use it?

Many thanks
 

ubuysa

The BSOD Doctor
I can't give you a definitive answer, but if the new drive shows up in Windows then it's fine and no BIOS changes should be needed.
 

Oussebon

Multiverse Poster
As above, sounds like you're fine, though there is one thing you might want to check.

The board has 2 M.2 slots.

M.2_1 supports PCIe and Sata devices

M.2_2 supports only PCIe devices.

The motherboard manual page 1-20 shows you which is which:
M.2_1 is the slot nearer the bottom of the motherboard. M.2_2 is the one a little bit down from the CPU.

PCIe devices here will mean things like very fast NVMe SSDs like the Samsung 970 Evo.

The BIOS has different options for each of those 2 slots. These are outlined on page 46 of the BIOS motherboard:

M.2_1 lets you toggle Sata / PCIe. It seems you have the correct setting for that or else your drive wouldn't be working...

M.2_2 is PCIe only but has a toggle for PCIe 3.0 x2 or PCIe 3.0 x4.
x4 is needed for full speeds on fast SSDs like the 970 Evo
x2 is half the speed and is okay for slower, very budget level, PCIe SSDs.

Running M.2_2 at PCIe 3.0 x4 disables Sata ports 5 and 6 (that's not unusual on these motherboards). The motherboard manual page 1-12 shows you which Sata ports 5 and 6 are. They're the ones closest to the bottom of the motherboard.

So:
M.2_1 seems fine.
M.2_2 clearly works but you probably want to check you have the right speed.

If you have a slower SSD in M.2_2, x2 is fine and x2 means you get to keep Sata ports 5 and 6 operational.
If you have a very fast NVMe SSD in there, you'll want PCIe x4 but make sure nothing's plugged into the bottom 2 sata ports of the mobo.

You can go into the BIOS and double check the setting.

Or, if you have a very fast SSD in M.2_2, you could download crystaldiskmark, run the test, and if you're getting your full sequential speeds on the SSD, you know you're fine :)

Of course if you bought the PC from PCS with an SSD and they put it in M.2_2 then it should already be running at full speed!
 

[email protected]

Active member
Thanks guys. After initial install did a speed test. The after watching a video I went back into Advanced BIOS and there was a setting for the M2-2 clot to change from x2 to x4. I applied this and the drive as indicated now shows almost double read/wrire speeds so seems a result. So I note the comments that I need to revert it back to x2 if I want to use the SATA 5/6 ports
 
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