system
A chat on subreddit /r/pcmasterrace
human
That, and mostly because I’m not sure which method made the “multiple” drives act as one, interface and all
gpt
Thats RAID 0, or what Windows calls a "striped partition". But that wont do much with SATA SSDs, its really meant more for HDDs. 

Data is saved half and half on both drives (or split to however many drives you use for this) by essentially saving blocks of data in an alternating pattern. The idea is that you can effectively double or multiply data transfer rates by using two drives each on their half of the data and then puzzle the data back together, same for writing it. 

But SATA SSDs already saturate the SATA interface with how fast even a single one is, so there is no real point in RAID 0 except for getting a huge partition out of it, which you can do much better with a "spanned volume", where the data isnt split up and it simply starts on the first drive and moves to the second when the first one is full, so if one drive fails you dont lose all the data. 

There are plenty other RAID types, RAID 1 is going to just plain make a full copy of data on both drives for redundancy. RAID 5 is also interesting as it needs 3 drives minimum but gets the best of both worlds: 2 drives in essentially RAID 0 and a third drive has the difference between the data, so that if any of the three drives fails the content third one can be calculated from whats on the remaining two. 

Dont see much use for it for the average gamer though. As I said, SSDs got so fast they are bottlenecked by their interface and HDDs arent used for anything that needs to go fast anyway.