Run speed

Run speed is the rate at which a character moves.

Run speed is the same for all races.

Barbarian and Monk classes get bonuses to run speed. All other classes have the same base run speed.

Modifiers of run speed:

Enhancement bonus (do not stack with each other):
 * Striding item effect which is commonly found on boots or rings (listed as 5%, 10%, 15%, 20%, 25%, or 30% speed bonus; actual bonus is 4%, 8%, 12%, 16%, 20%, 24%).
 * Longstrider spell (listed and actual 15%)
 * Expeditious Retreat spell (listed and actual 25%)
 * Thief-Acrobat: Showtime boost (listed and actual 25% run speed bonus, also other skills bonus)
 * Haste spell (listed 40% actual 32% run speed bonus, also 15% attack speed bonus)
 * Shadow Walk spell (unlisted but actual 40% run speed bonus, also 50% concealment)
 * House Phiarlan Favor Reward the Phiarlan Pendant of Time's Warp Time spell (unlisted but actual 50% speed bonus, only in public areas).

Base increase (stack with each other and highest Enhancement bonus):
 * Fast Movement (barbarian class feat) (verified 10% at Barbarian level 1)
 * Fast Movement (monk class feat) (unverified +5% per 3 levels of Monk: 5% at 3, 10% at 6, 15% at 9, 20% at 12, 25% at 15, 30% at 18).
 * Thief-Acrobat II (verified 10% possible at Rogue level 12)
 * Barbarian Sprint Boost (verified 35-50% possible at Barbarian levels 1-10: 35% at 1, 40% at 4, 45% at 7, 50% at 10)
 * Ranger Sprint Boost (verified 35-50% possible at Ranger levels 1-10: 35% at 1, 40% at 4, 45% at 7, 50% at 10)

No change
 * Abundant Step does not increase run speed, nor is the distance jumped increased with a higher run speed.
 * Type of armor worn.
 * Race
 * Sex
 * Strength, Constitution, or length of run time (you don't get Exhausted from running)

Reduced by:
 * Carrying capacity: reduces speed when you are weighed-down:
 * Load: Light (0% to 33.33% load): no penalty.
 * Load: Medium (33.34% to 66.66% load): -4.3%.
 * Load: Heavy (66.67% to 100% load): -11.8%.
 * Load: Other (more than 100% load): -30.8%.
 * Some enhancements such as Stalwart Defender and Defender of Siberys Defensive Stances (1/2 or 1/3 speed), Monk's Mountain Stance
 * Some spells, such as Slow, Blindness, Ray of Exhaustion, Stinking Cloud, Sleep, etc.
 * Some Weapon enhancements, such as Crippling, Stench, Paralyzing, Strength Sapping, Tendon Slice, Stunning, Slowburst, Limb Chopper
 * Some melee special attacks, such as Hamstring, Sap, Stunning blow
 * Being fatigued after using the Barbarian Rage ability
 * Using the Sneak ability
 * Jumping (verified)
 * Flying (the spell cast by the Storm Reaver in The Reaver's Fate and Reaver's Refuge (Note that the Swim skill reportedly determines travel speed when flying. It does not affect speed when jumping/falling without Fly.)
 * Being Harried due to beign hit whilst high level dungeon alert is active

Useful data from:
 * Help! I was robbed of my 30% striding! (part 87 of "Things don't work as advertised") thread
 * Help! I was robbed of my 30% striding! (part 87 of "Things don't work as advertised") thread update
 * fastest mover thread
 * Striding/Monk Speed/Longstrider, do they stack? thread
 * Haste Types thread