Poor Sample Performance

[josemendez]

That make a lot sense. It accounts for how the frame rate "slowly" dies now.

I changed the solver to Simulation Order: Late Update, Disabled V-Sync and set my TimeManager as follows.



With the new setting I believe I'm still seeing the death spiral, albeit much better than the death cliff I saw before.



Experimenting with smaller values of Maximum Allowed Timestep does seem to help but not as much I had hoped. At .02, the lowest value it seems to allow I was able to achieve my highest stable frame rate, ~25 frames/sec. Obviously, the fluid behaves very oddly.



A reasonable max step of .1 manages about 15 frames/sec. Is it abnormal to have to change the Fluid Viscosity demo scene to late update to achieve a reasonable frame rate? it seems likely it would have already been set that way if it were actually necessary.

Yep, it is not normal to have to use LateUpdate(). We benchmarked the FluidViscosity sample scene in several CPUs, and there are the frame times for them (in milliseconds):

Windows - Intel Xeon E5 (quad core): 8.7 ms/frame (114 fps)
Mac - Intel Core i7 (quad core): 11.2 ms/frame (89 fps)
Mac - Intel Core i5 (dual core): 17 ms/frame (58 fps)

None of them come even close to the +30 ms/frame you're getting. Make sure you try with all profilers disabled (both Obi's and Unity's, even when in non-deep profiling mode). Also try a standalone version of the scene, to rule out editor issues.

AMD's bulldozer-based CPUs are known for really low IPC (instructions per cycle) so they are usually way slower than other CPUs, specially for sequential tasks where the amount of cores is not relevant. However performance should not really suffer that much, since most of Obi is parallelized.