Fast Casting



Fast Casting is the Mesmer primary attribute, which means that only characters who have chosen to be a primary Mesmer can put points into this attribute. While Fast Casting has a limited number of skills linked to it, the passive benefit it provides is more than enough by itself. Unlike the primary attributes of other professions (which have simple, linear progressions), the effects of Fast Casting on spells have an exponential progression.

Guild Wars description

 * "Fast Casting decreases the activation time of your Spells and Signets. (No effect for non-Mesmer skills with an activation time less than 2 seconds.) In PvE, each rank of Fast Casting decreases the recharge time for your Mesmer Spells by 3%."

Effects of Fast Casting


Fast Casting has three effects:
 * Reduces spell casting time exponentially by approximately 4.73% for each rank. (9 ranks reduces casting time to roughly 66.1%; see below)
 * Reduces spell recharge time by 3% per rank (9 ranks reduces times to 73%)
 * Reduces signet activation time by 3% per rank (9 ranks reduces times to 73%)

Also note:
 * FC is cumulative with items that halve casting times or halve spell recharge times.
 * FC affects all mesmer spells and signets.
 * FC affects non-mesmer spells and signets with activation times of 2s or more.
 * FC does not affect aftercast delay, which prevents activation of a second spell for 0.75s.

Analysis

 * Determining ideal investment: Because of the progressive cost of attribute ranks and the effects of aftercast delay, players believe that the sweet spot for Fast Casting is 7–9 ranks. This allows mesmers to set two other attributes to 10 & 12 respectively. (Obviously, if a build includes several FC skills, it makes sense to invest more than 9 points.)
 * More spells more quickly: Fast Casting allows mesmers to cast more spells. All other things equal, a mesmer could cast four 1s spells (with FC=9) in 5 seconds whereas other professions would take 4.5 seconds to cast only three.
 * Recast spells more quickly: Faster recharge means that mesmers are able to recast hexes on enemies before the original hex expires.
 * Shutdowns: In order to interrupt and otherwise prevent opponents from using skills, the mesmer has to be quicker on the draw. FC helps mesmers apply pre-emptive hexes early enough and also allow mesmers to be available to interrupt skills presently activating.
 * Avoiding long activations: Some mesmer (and secondary profession) skills normally take too long to cast in PvE or PvP. Diversion and Backfire would normally take 3s to cast; with FC=9, they can be cast in just over 2s.

Calculations
The exact reduction for spell casting time is:

This translates to approximately 4.73% per rank, applied multiplicatively, so 9 ranks of Fast Casting reduces casting time to roughly 66.1% (0.9559) rather than roughly 57.4% (1 - 9 × 0.0473).

Percentage reductions
The following table shows the reduction in casting times and the relative speed improvement.

Adjusted casting times
This table lists the reduced casting times of spells that would normally take from one-quarter to eight seconds to cast (rounded to the nearest hundredth of a second).

Associated skills
Currently there are only nine Fast Casting skills, more than half of which are elite. Most Fast Casting skills relate to the activation or recharge time of spells or signets. Fast Casting skills also include Symbols of Inspiration, a copying skill similar to Arcane Mimicry.