Ok, to get grass to show pretty far away does require Extended Distance Scaling. However, just having grass on Very High is sufficient to appear like the PS4 version. Allow me to demonstrate with the clearest PS4 grass picture that I could find (most of them are low res). First, Very High on PC then the PS4 image then Ultra (Edit: a lot easier to see if you open them up in different windows):
What's clear from these images is that Very High looks exactly like the PS4 image while Ultra interestingly adds ACTUAL SHADOWS to every tuft of grass. That's insane and why it has such a performance cost. I thought it was only adding an AO-like shadow but no, it's an actual dynamic shadow.
Unfortunately, as I said, I couldn't find any good high res PS4 shots that show how far the grass renders but here's a comparison of Very High and Ultra without any Extended Distance Scaling:
Ultra adds a lot of grass density, especially further away, even without the extra scaling, and the shadows make the grass pop out quite a bit better.
So, basically, Grass on Ultra by itself is significantly better looking than on PS4. I wasn't able to compare to PS4 with and without Extended Distance Scaling but, given how much of a toll it can have, I'm going to go out on a limb and say that PS4 probably doesn't use it.
Concerning your settings, you have a few on that can have a pretty big impact on performance but aren't that noticeable or, in my opinion, aren't worth it. The first is Reflection Quality Ultra. The Nvidia guide (you know which one but for ease of access:
http://www.geforce.com/whats-new/guides/grand-theft-auto-v-pc-graphics-and-performance-guide) has that costing about 17% over Very High. Honestly, unless you love staring really closely at reflections, the performance hit is not worth it if you're chasing either locked 60 fps or raising other settings. Next, you're using 4xTXAA which just sucks up performance, ~20% compared to FXAA. Personally, I would turn down/off MSAA, turn on FXAA, and just raise every other setting, like grass which would need a 30% trade-off to go from High to Ultra which these first two suggestions get you. Thirdly, you're using the PCSS shadows which, in combination with all of your other shadow settings, will take up another 10% or so of performance over Softer shadows which I feel look about as good as Softest while giving you back a huge number of frames. Lastly is Long Shadows. I haven't been able to really spot a difference, and the Nvidia guide says that it's pretty subtle. They only measured a 3 fps difference with it on and off but, hey, that's 5% performance. One final thing is that the AO setting doesn't actually change anything, so you actually still have it on I think.
In conclusion, for having ~4x the theoretical performance of a PS4, you can get double the framerate (that's 2 of the 4x right there), markedly better and way more shadows everywhere (all objects and grass rather than some excluded such as power lines; headlight shadows rather than none), and possibly denser grass. You might even be able to keep some MSAA. It's also not known whether there are additional effects that PCs are doing that consoles are not given how hard it is to get the exact same comparison conditions between PC and console as much as Digital Foundry tries.
