MSI GT72VR HDD upgrade

Hey guys,
I recently purchased a brand new MSI GT72VR Dominator pro with a GTX 1070 and 128 GB SSD plus 1 TB HDD. After a couple months my HDD has come down to 30 GB of free space (I only have games on that HDD.) And so I decided to order a new 4 TB HDD from Amazon. The HDD is expected to arrive next week and so I decided to do some digging in to the option of ADDING rather than swapping my HDD so I could keep the extra 1 TB. Unfortunately, a video I found in YouTube isn't relevant to how the GT72VR are shipped, where there is no 4 m.2 slots bay but only 1 m.2 slot so that method is irrelevant. I was wondering if there's a different way to connect an extra HDD without taking out the disk tray.
Anyone who is willing to help can use this link for reference to how the laptop looks under the hood. http://www.laptopmain.com/msi-gt72vr-disassembly/
Lastly I have a question about swapping the HDD if it comes down to that- I plan on transferring everything I have on the 1 TB drive to an external HDD and then install the 4 TB drive in my laptop and move everything back. Could that cause any problems with steam or the games I have installed or should it be fine? Windows is installed on the SSD.
Thanks in advance!

 

The only feasible solution is to replace the optical drive with the HDD by buying a cady but anything beyond that is not possible. Your other option is buying an external USB 3.0 enclosure.

 

I think this should be fine, just make sure the new drive is showing up with the same drive letter.

You could also clone the 1TB disk to the 4TB one and then expand the partition.

 

I think replacing the optical drive is a bit too complicated for me plus it's not worth the effort for an extra TB . This might sound noobish but I'm new to this side of PC building; is there no SATA cable that connects 2 drives to one motherboard plug? I know there's one for power but is there nothing for data as well?

Could you expand on that a little bit? I have no experience in the HDD field beyond installing one.

 

Even if you could find such a cable - do you have where to mount the HDD?

In any case, SATA is not duplex so you would only be able to address one HDD at a time making the whole ordeal pointless.

 

There is physical space as if there's meant to be a way to connect another one but they cut that option out unless you specifically ask for it and pay extra

 

Pick up a dock like this one - they're really handy. If you have USB3 or eSATA ports, you can get pretty decent speeds.

There's a lot on google or this forum about cloning drives - do some searching around and reading.

 

Still, SATA, unlike SATA Express, is not duplex meaning that it would be pointless to have 2 drives connected to the same port.