Two events have fortuitously coincided for me recently: I picked up playing Just Cause 3 again (which has almost unbearable load times on the PS4), and I also ended up with a spare 500GB SSD as a result of a PC upgrade. Problem, meet solution?
Now I know from the outset that this is kind of a ridiculous value proposition since the PS4 Slim still has a SATA II interface, and even a used SSD is pretty valuable, but just for kicks and giggles I decided to see if it would make the Just Cause 3 loading screens any less torturous.
I repeated each of the following tests three times for consistency and took the average (variance was <5%). Here are the results (all times in seconds).
Cold start to "press x to start" screen: 40 w/ HDD, 32 w/ SSD
Logging in for online features: 19 w/ HDD, 14 w/ SSD
Loading saved game, Baia province: 40 w/ HDD, 22 w/ SSD
I was actually pleasantly surprised by these results. I mean it's obviously bottlenecked by several factors: the JC3 servers when logging in, the intro videos on cold start, and more generally the SATA II interface and CPU. But the saved game / checkpoint reload times are probably the most significant contributor to my frustration, and improved nearly 50%. I'm not sure if that's worth the opportunity cost of selling the SSD, but it's way better than nothing!