BLUS31197 Drakengard 3 low performance

Try changing the following settings:

Preferred SPU threads to 2 instead of 1
Enable SPU loop detection
ASync with Shader Interpreter

Otherwise your settings are pretty much correct. You shouldn't be losing much performance if any when scaling to 1080p from 720p with those specs. Ultimately, you can try rendering at 900p and using FSR to upscale to 1080p with RCAS 50% or 90%.

Note that even with a good CPU, you will find some frame drops below 30 FPS as the game is poorly optimized, I get some even with my 2700X (e.g. on the beginning, when the dragon comes down to throw some flames).

I updated to the new version and changed the settings to the ones you mentioned, and performance increased noticably by about 10 FPS, the game now runs at about 50-60FPS on 1080p with some drops to 40 FPS or lower when there's enemies on the screen. Sometimes it hits 60FPS in confined areas where there isnt much to render. I tried running it with 3 SPU threads as well but I couldn't notice any change.

I used a bit of the first mission to benchmark the changes.
On both SPU thread settings the very first screen runs at about 50FPS (where you're fighting the guards), when the dragon throws flames once you go through the gate that number dropped to 20FPS on 3 SPU threads and 29FPS on 2 SPU threads. Performance was otherwise consistent between the two, the titan fight was 60FPS throughout.
I've uploaded the logs for both sessions.

I've also gone and tried it on 720p again and the performance is almost identical to 1080p (in some places actually worse, dragon fire tanked FPS to 16), so what you said was true.
If there's anything else I could tick on or off that you think would improve performance do let me know, though this is more or less playable at this point.