m15 R1, why don't I have a DATA (D) drive?

Welcome to the Dell Community @Escafil 

Did you include the second drive option with your purchase???

If you did and the drive is not installed then you would need to contact Dell Support.

Best regards,

U2

I got all the defaults. I'm just wondering if they changed it up the next year, because my sister got the same exact one just the next year.

@Escafil 

Ah they must have changed the default options.

If I remember correctly your sisters OS drive could be an SSD and an HDD for storage???

The only better option would be to have an SSD for the OS and an SSD for storage.

Regards,

U2

@Escafil  You have an SSD that's only 8GB?  That isn't even enough to install Windows onto.  Are you sure you don't have a spinning hard drive that has an 8GB integrated cache?  These are called SSHDs, or solid state hybrid drives.  But in that case the 8GB cache isn't usable as an entirely separate drive, in fact you shouldn't even see it in Windows.  It's just a cache internal to the drive itself that the drive manages with its own firmware completely independently of Windows.

But whatever the case, it does sound like your systems were ordered differently.  I'm not sure what you mean that you just got "the defaults" given that Dell typically has lots of configurations offered as different baselines, each of which can be customized to some extent -- and even the multiple baseline configurations can vary over time and definitely based on region.  As for 931 GB vs. 921 GB, even if that wasn't a typo, those would both be 1TB drives, but maybe you've got a larger hidden partition for some purpose on your system.

It's the hybrid drive for mine. I checked what partians I have and all I have is a 12 GB and a 1 GB recovery drives. There are 2 others but they are very small. I'm just disappointed that I don't have that extra 200 GB. Can it be added later?

@Escafil  Yes it can be added later.  Go to support.dell.com and enter your Service Tag or system model, then go to the Documentation section and grab the Service Manual (or Owner's Manual/User Guide if you don't see the Service Manual as a separate document).  That will have step-by-step instructions for removing and installing every component in the system, complete with diagrams.  If you have a hybrid drive, then you should have an unused M.2 slot that you can use for installing another SSD.  There are M.2 SATA and M.2 NVMe SSDs.  NVMe SSDs are faster.  I believe your system supports both, but confirm that by checking your system's specs, which should also be somewhere in the documentation available on that site.  The most common SSD size is M.2 2280 (22 mm x 80 mm), and the only thing you might need to install one is a fastening screw to hold the SSD down on the motherboard, since you might not have that in your system if it didn't come with an M.2 SSD from the factory.  But many M.2 SSDs come with one anyway.

@Escafil 

SSHD's use on-board Cache "Most times 8GB"

It does not show as a partition as it does not use disk space.

I had to wait until I cam in today just to make sure.

Three different SSHD's two 1TB and one 500GB.

Regards,

U2

You got the right device.

And so did your sister.

The defaults were changed by Dell, that caused this confusion.