Attack rate

The Old School RuneScape Wiki also has an article on: osrsw:Attack speed

The attack rate, often called attack speed, of a weapon or a monster determines the interval at which either a player deals auto attacks with a weapon or a monster attacks. This is a factor which is often considered by players when forming strategies in legacy combat, especially in player-killing. In EoC it is considered less often than ability damage, unless attempting to maximise damage dealt to the absolute fraction of a percent (in PvM especially).

Attack rates are represented by a bar on which there are several possible values ranging from either slowest to fastest weapons, or 1 (fastest) to 10 (slowest) rate monsters. The delay time in seconds between each attack is equal to $0.6t$. Where $0.6$ represents the length in seconds of a single game tick and $t$ is the amount of game ticks.

The 0.6-second-long "game tick" is the basic unit of time the game's engine is built upon. All attack rates are an integer multiple of this tick time.

Weapons

The speed of a weapon is represented by a word on the tooltip of the weapon. These primarily range from "average" to "fastest".

Speed	Types of weapons
Fastest (2.4s)	Claws, daggers, defenders, maces, scimitars, whips, goliath gloves Crossbows, darts, hexhunter bow, throwing knives, seercull, upgraded bone blowpipe Wands, Orbs
Fast (3.0s)	Hastae, hatchets, longswords, rapiers, swords, Saradomin sword Most shortbows, Zaryte bow, Crystal bow, chinchompas, Chakrams, Decimation None
Average (3.6s)	Battleaxes, halberds, mauls, pickaxes, warhammers, spears, two-handed swords Javelins, most shieldbows, salamanders, thrown axes, two-handed crossbows Staves
Slow (4.2s)	None None None
Slowest (7.2s)	None Dark bow None
Random (???s)	Dwarf multicannon

Monsters

The attack rate of monsters is represented by a numeric value in game ticks.

Monster Examine, a Lunar spell, will display the attack rate (as well as other information) of a monster when used.

Rate	Members	Monsters	Notes
1 tick (0.6s)		Cave insects (Lumbridge Swamp surface); Scarab swarms; Koschei the Deathless (final form); Zimberfizz (during Soul Wars tutorial), Vanstrom Klause (during the Branches of Darkmeyer, final form), Scopulus (while enraged), Defence Pylons (Temple of Aminishi)	The monster attacks once every game tick. Hits are usually low, but extremely fast.
2 ticks (1.2s)		Rock lobsters; Abyssal leeches; Killerwatts; Commander Zilyana; Nomad (after going berserk); Bouncer (during Ritual of the Mahjarrat); Jellyfish variants; Vitalis	The monster attacks every other game tick. Hits are fast, but usually low/inaccurate.
		Bal'lak the Pummeller	Extremely fast, but generally low hits.
3 ticks (1.8s)		Kree'arra; Dessous; Dessourt; Karamel; Damis (second form); Bush snakes; snakes on Mos Le'Harmless; all members of the Dwarven Black Guard; Yk'Lagor the Thunderous; Blink; Kal'Ger the Warmonger (in final phase with Primal maul); Ripper Demons; Wyverns; Twin Furies; Araxxi; Solak at certain points	Hits are quite fast, but generally lower than those with slower attack rates.
		Shadow-forger Ihlakhizan	Low hits but rapidly.
4 ticks (2.4s)		All normal chromatic and metal Dragons, including the King Black Dragon; Skeletal wyverns; Earth warriors; Waterfiends; Aquanites; the Phoenix; Strykewyrms; Nex; Araxxor; Corporeal Beast; Yakamaru; Kal'Ger the Warmonger; Tormented demons; Giant Mole; Kalphite Queen; Karil the Tainted; Mutated jadinkos; Koschei the Deathless (first three forms); TzTok-Jad and TokHaar-Jad (melee only); Vyrewatch (Temple Trekking and Darkmeyer); Vyrelords and vyreladies; TokHaar-Hok; Glacytes; Glacors (after Glacytes are defeated); Swamp monster head; Gregorovic; Helwyr; Vorago; Telos; Nex: Angel of Death; The Magister; Dreadnips	The standard attack rate and the most common speed for monsters.
		Most bare-handed monsters, including bare-handed humans; Wizards and Dark wizards; Elvarg; Melzar the mad; Monks of Zamorak; Barbarians; Most bosses in Daemonheim; Flesh Crawlers; Cockroach soldiers; Ice warriors; Ice elementals; Dungeoneering dragons; Mysterious shades; Skeletons in Daemonheim; Hobgoblin Geomancer	Most common attack rate. The majority of these monsters, if not all, use melee and/or ranged attacks.
5 ticks (3.0s)		Nomad (before going berserk); Fire giants; All Revenants; TzHaar-Mej and TokHaar-Mej; Celestial dragons; Swamp snakes; Nezikchened; Barrelchest; Pest Queen; Werewolves; Abyssal walkers; Gluttonous behemoth; Vyrewatch (ouside of Darkmeyer only); Necromancers; Vanstrom Klause (during The Branches of Darkmeyer); Glacors; Warped Gulega; Tribesman; Vindicta; Solak	Generally hits harder and more often than monsters with faster attack rates.
		Forgotten warriors; Forgotten rangers; Forgotten mages; most zombies holding weapons; Zombies in Daemonheim; dwarfs; Moss giants; Ice giants; all Revenants; Mercenary leaders; Gluttonous behemoth; level 68 Chaos dwarves	Generally hits harder and more often than monsters with faster attack rates.
6 ticks (3.6s)		Queen Black Dragon; TokTz-Ket-Dill; K'ril Tsutsaroth; General Graardor; Jungle demon; Ahrim the Blighted; Warriors and Market guards in Rellekka; Dreadnaut; Rammernaut; Skeletal horror; Runebound behemoth; Balance Elemental; Decaying avatar; Beastmaster Durzag	Attacks are slow, but generally hit high.
		Hill giants; humans wielding crossbows; Forgotten warriors with 2h sword or maul; Brutes; Ramokees	Hits are slow, but can be quite damaging, particularly from brutes and forgotten warriors.
7 ticks (4.2s)		Chaos dwarf hand cannoneers; Dharok the Wretched; Black Knight Titan; all Grotworms	Slow attacks, but usually with high accuracy and/or maximum damage.
		White knights	They hit with two-handed swords.
8 ticks (4.8s)		TzTok-Jad and TokHaar-Jad (ranged and magic); Dad; Vanstrom Klause (during The Darkness of Hallowvale); most familiars	Very slow attacks, but high maximum damage and/or accuracy.
		Bovimastyx	Bovimastyx are only encountered in Daemonheim.
9 ticks (5.4s)	N/A	None	No monster attacks with this rate.
10 ticks (6.0s)		Dreadnip (prior to the Evolution of Combat)	Attacks are extremely slow, but compensated by high damage and accuracy
Random (???s)		Cave horrors; Necrolord; Gravecreeper; Char	The monster's rate is indeterminate, or the monster has an irregular attack rate.
		Astea Frostweb, To'Kash the Bloodchiller, Unholy cursebearer	The monster either has an irregular attack rate, or its rate is indeterminate.