Welcome to the Dell Community @pluriel 

Does it have an exact model number???

Since you did not post what version here are the 4 that are available.

Alienware m15 Setup and Specifications:

https://www.dell.com/support/manuals/us/en/04/alienware-m15-laptop/alienware-m15-setup-and-specifications/set-up-your-alienware-m15?guid=guid-5be30a50-676e-4b11-a017-f60b125ae6d5&lang=en-us

Alienware m15 R2 Setup and Specifications:

https://www.dell.com/support/manuals/us/en/19/alienware-m15-r2-laptop/alienware-m15r2-setup-specs/set-up-your-alienware-m15-r2?guid=guid-5be30a50-676e-4b11-a017-f60b125ae6d5&lang=en-us

Alienware 15 R3 Setup and Specifications:

https://www.dell.com/support/manuals/us/en/19/alienware-15-laptop/alienware-15-r3-setupandspecifications/set-up-your-computer?guid=guid-8bcbee03-02e5-4cce-96e8-5952c4e7a877&lang=en-us

Alienware 15 R4 Setup and Specifications:

https://www.dell.com/support/manuals/us/en/04/alienware-15-r4/alienware-15-r4-setupandspecifications/set-up-your-computer?guid=guid-8bcbee03-02e5-4cce-96e8-5952c4e7a877&lang=en-us

Best regards,

U2

@pluriel 

 Does it support SATA password locking?

Alienware m15 Service Manual:

https://www.dell.com/support/manuals/us/en/04/alienware-m15-laptop/alienware-m15-service-manual/before-working-inside-your-computer?guid=guid-5d3b1051-9384-409a-8d5b-9b53bd496de8&lang=en-us

Regards,

U2

Hi U2. It's the first M15 (not R2) I'm looking at (https://www.dell.com/en-us/shop/laptops/15/spd/alienware-m15-laptop). The first link answers the third question I posted. There's no info there regarding the rest.

Regarding SED support I'd like to know if the laptop supports the hardware encryption feature of such disks - it requires BIOS support as I understand: https://docs.microsoft.com/en-us/windows/security/information-protection/encrypted-hard-drive 

Thanks

@U2CAMEB4ME 

Yes, it seems HDD passwords are supported, according to the service manual. Doesn't mention if this applies to both SATA and MVMe drives, although from what I have read on the subject this is only supported on SATA drives. Do let me know if you have any info to the contrary.

There's no mention of SED support. Do please let me know if you have any info about this.

Cheers.