You can speed up playback by disabling the solver, disabling fluids collisions, emissions, and fields, disabling display options, and by caching your fluid.
The calculations that take place during solving slow down playback. To temporarily disable the fluid solver to speedup the playback of the rest of your animation, change the Contents Method of the fluid properties from Dynamic Grid to Off in the fluid container attribute editor. The contents of the grid are not lost when you do this. See Contents Method.
Alternatively, turn on Disable Evaluation in the Dynamic Simulation section of the fluid container Attribute Editor. See Disable Evaluation
To speed up playback, you can temporarily disable collision of fluids with attached geometry, ignore all connected emitters, or ignore all connected fields. In the Dynamic Simulation section of the fluid container attribute editor, turn off the Use Collisions, Use Emission, and Use Fields options, respectively.
Turning off the Shaded DIsplay option or setting Boundary Draw to None in the Display section of the fluid container Attribute Editor can speed up playback.