Using RAID 0 to increase the storage performance of a desktop used to be in vogue. Then it wasn't. Now it is again. Once upon a time, you could sling a couple of Western Digital Raptors together, fire up a level in Battlefield 2 before anyone else, get the plane and dominate the map. Solid-state drives like Samsung's 950 Pro deliver orders of magnitude more performance than those mechanical products.
After poring over our results, we figured out why a single drive's latency is better than two 950 Pros in RAID 0. In a striped configuration, the array uses Microsoft’s RAID driver and not Samsung’s custom NVMe software. Windows sees the array as an Intel chipset volume. It's possible that Intel might be working on a custom RAID 0 driver, but we aren't counting on it. Fortunately, although Samsung's driver enables lower latency, we doubt anyone will "feel" the difference.
Using RAID to increase capacity or add redundancy is another story. Two 256GB 950 Pros don't make a lot of sense from a capacity standpoint since one 512GB drive costs less than the pair together. Three drives in RAID 5 are technically viable, but you have to be willing to lose one drive's worth of capacity to distributed parity. Aside from those corner cases, two NVMe SSDs in RAID just isn't worth the trouble or expense. The technology is back to where it started: in the server rack and high-performance workstations.
Now that we have the hardware capable of insanely high storage performance, we need software to take advantage of it. I'm not closing the book on RAID for the sake of higher performance just yet. In time, the applications will catch up and we'll again look for ways to squeeze more speed out of our components. Until then, storage is in a really good place.