After playing a bit on PS4, I got curious what the input lag difference is compared to PC, as even the menus in the PS4 version feel laggier than on PC.
Short answer: Looks like it's 3 frames slower on PS4 (aka 50 ms). Which is pretty significant, especially with the overall input lag being 90ms (as measured by
https://twitter.com/WydD/status/1052836115017854976).
Long answer...
Since the method relied on recording footage of both versions at the same time, I decided to compare loading times too for the heck of it.
Loading times:
Title screen to main menu on PC: 7.4 seconds
Title screen to main menu on PS4: 17.1 seconds (that network thingie takes its sweet time)
Main menu to character select on PC: 6.8 seconds
Main menu to character select on PS4: 11 seconds
Stage select to ingame on PC: 14.4 seconds
Stage select to ingame on PS4: 20.6 seconds
Average input delay difference: 3 frames slower on PS4 (aka 50 milliseconds slower)
I don't have an easy way to test the total input delay on a specific platform, but WydD on twitter tested the total input delay for the PS4 as being 90.4ms at launch.
Here's the PC I used for the test: i7-4790k, gtx 1080, 16gb ram, Win 7 64-bit, SC6 installed to an SSD
The PS4 is a PS4 Pro with a stock harddrive and I used an Intensity Pro 4K with PtBi to capture the PS4 footage. This capture card has an extremely low amount of capture latency. The lag with the capture card is less than 1 frame based on my tests (I had PS4 running with an HDMI splitter leading to capture card and a monitor, and they both showed the same frame in a 60fps game).
I did the input test by having two PS4 controllers connected to the PC and PS4 (wired to PC, wireless to PS4) and then trying to press the same button at the same time (I did this many times and got the average, which should be a good indicator for what the actual difference is).