(last updated: 07/13/21)
Victory in a CSYS fight can often involve combining multiple bonuses together. In almost all cases, different "flavors" of bonuses are compatible. You can, for instance, combine SMASH with DM/Speed, ES with DM/Speed, or DM/Power with EX. In each of these pairings, the first is a power bonus, the second is a attack to-hit bonus. Mix and match your types to win!
Mixing bonuses of the same "flavor" -- to-hit, power, reaction, defense, and recovery -- is called "stacking." If two effects "stack," that means both bonuses work together. If two effects do not stack, that means that only the stronger of the two bonuses will be effective.
For example, Rush and Endure stack. That means a +% Rush bonus combines with a +% Endure bonus, for a net gain of +% to-hit.
However, Rush and DM/Speed do not stack. That means if you Rush for +% to-hit, and then use DM/Speed for +% to-hit, your Rush has been wasted; only the higher of the two amounts (DM/Speed's +% to-hit) is included in the calculation.
That said, here is a list of the bonuses that do not stack.
To-hit Bonuses That Do Not Stack
*+rush with +dm/speed
*+dm/speed with +endure bonus
*+ex (Resolve) with +dm/speed
*+focus with +endure bonus
*+focus with Ambitious bonus
*Trait-based speed/to-hit bonuses
*+clarity/interrupt with +endure bonus (takes whichever is higher)
*+clarity/interrupt with +dm/speed (dm/speed is faster)
*+clarity/interrupt with +EX or parry
*BOLD trait no longer stacks with TOP
Power Bonuses That Do Not Stack
*+smash with +dm/power
*+smash or +dm/power with +calculated (Insidious)
*+ES does not stack with S Smash, +DM/Power, or +calculated
*+nova cancels out the DRIVEN effect
Reaction Bonuses That Do Not Stack
*+evade with +dm/alertness
*+dm/alertness with traits that grant an Alertness bonus (Intensity, etc)
*+evade with the reaction bonuses of +clarity
*Trait-based reaction bonuses do not stack with each other
Defense Bonuses That Do Not Stack
*+brace or +dm/guard with Diehard
*+brace with +dm/guard
*Brace's passive with Diehard
*+shield does not stack with S Brace, +dm/guard, or Diehard.
Recovery Bonuses That Do Not Stack
*+dm/recovery with Calm bonus
*Trait-based Recovery bonuses do not stack with each other
*Health ticks from Energize do not stack with Recovery or Restore ticks.
The above list is complete as far as we know. This means things not on the above list should dovetail together. So here are some examples of things that do combine:
Examples of Bonuses That Do Combine
*+rush with EX effect (Parry)
*+rush with +endure bonus
*+brace or +dm/guard with Fearless
*Pretty much everything else
- 7/12/2016 - +dm/speed and +endure bonus don't stack
- 7/13/2016 - +evade and the reaction bonuses of +clarity do not stack
- 2/9/2018 - Per CSYS Update #1385, Skilled no longer stacks with other trait-based speed boosts.
- 3/4/2018 - Clarity/interrupt does not stack with DM/speed or Endure bonuses.
- 3/21/2018 - Clarity/interrupt no longer stacks with EX/Parry, BOLD no longer stacks with TOP. Also added +ES, +shield, and ENERGIZE.
- 7/13/2021 - Nova now cancels Driven per CSYS Update #1736.