Solely Based On Proven
Source Book Rulings From Advanced Dungeons And Dragons 2nd Edition: Which Quotation Below Is / Are Correct, And Which Is / Are Wrong?
"As you all know a round takes 6 seconds (ok, you all didn't know...). A speed factor of 4 means it takes you 4/10 of a round to strike, so you can make 2,5 strikes a round. This speedfactor can be raised by magical means (haste), weapons (bows are usually faster as 2-handed swords), and of course profincy, as the matter of fact, by going from master to grand master this is the only improvement."
"Here go, reading from the second edition's player's handbook (black and red edition), page 127, under the title 'weapon speed and intiiative (optional rule)'
each time a character swings a weapon, he places himself out of position to make his next attack. swinging a hammer is not as simple as tapping in a nail. A war hammer is heavy. Swing it in one direction and it pulls in that direction. It has to be brought under control and repositioned before it can be swung again. The user must regain his balance and plant his feet firmly. Only after doing all this work is he ready for his next attack.
Compare how quickly someone can throw a punch to the amount of time required to swing a chair to get a good idea of what weapon speed factors are about.
Weapon speed factors slow the speed of a character's attack. The higher the weapon speed, the heavier, clumsier, or more limited the weapon is. For the most part, weapon speed factors apply to all creatures using manufactured weapons. The speed factor of a weaspon is added to the intiative roll of the character to get his modified intiative roll.
there's another paragraph after all that, but it goes on to say how if the DM decides to use speed factors, he should use them for the monsters, as well as the PCs.
now, how this all equates in the much different format of baldur's gate, i'm not 100% sure, but that's the basis for speed factors in pen and paper, so i imagine it's real similar in the game."
Source Link: http://www.neoseeker.com/forums/327/t289536-speed-factor/
"Speed Factor: Each type of weapon has a Speed Factor, which determines at what point in the round the attack will actually be made. A Speed Factor of 4 means that at the start of each round of combat, the character will wait for 4/10ths of the round to pass, and then attack. Cumbersome weapons such as Flails and Crossbows have the slowest Speed Factors, and small weapons like Daggers have the quickest. Note that the Speed Factor of your weapon does NOT affect how rapidly you can attack with it (that is determined solely by your Attacks per Round), it simply reflects how long it takes between the time you issue the Attack command, and when the attack is actually made. It is important largely only for characters attacking from Stealth, where a quicker Speed Factor can give you a second chance at a Backstab (before you become visible) if you missed the first time."
Source Link: http://www.pocketplane.net/volothamp/chap2.htm