Hi LuckLock, can you please run a performance test and in your results? You can put "Atten : C7" in the feedback email so I can find it easily in our feedback system.
If it's running slowly, you can try one of the older (and less "safe") integrators, that may perform a lot better for you.
Trying to select a different integrator or compute device may help. Sometimes our testing can report a device as performing better then another, when that doesn't pan out in practice. Without getting too technical, some devices don't handle certain cases very well, and will fall off greatly in performance during those times.
Try playing around with the settings and see if something works well for you.
To access the integration and compute device settings, Select the sim icon (little gear in the left corner),
Simulation Settings tab, and look for the "Gravity" section.
In there you can choose IntegatorID and Integration modes, as well as the default compute device, and accuracy restrictions.
A brief overview :
Fixed -> This is the fastest, but will not respect accuracy. May cause bodies to fly out at high timesteps.
Unsafe Global Adaptive -> This is the default for Alpha 12.1, more respect for accuracy, but higher cost
Global Adaptive -> This is the default for Alpha 13, Our new in development integrator. Should have better performance (computationally), but may be slower (in fps) for now. Respects accuracy of the simulation. In a lot of cases this can be faster then the Unsafe version.
In regards to the collisions, try setting the Non Attracting body count to be lower. (We changed the particle spawning logic, so they spawn a minimum amount, which is related to the currently set cap)
To adjust this, go to Home -> Settings -> Performance, and you will find the options there.
We're still collecting performance data to come up with better defaults. But for specific computers, you'll get much better, and smoother gameplay if you adjust this manually.
It will tone down the amount of stuff flying off, but it will perform a lot better.