Assuming you hit on a 2, you get 19 "units" of damage out of 20 attacks, + 1 extra unit per critical threat, per critical multiplier (above x1). So 18-20 threat gives 3 extra sets of damage in those 20 attacks for a x2 multiplier weapon, or 6 extra for a x3 multiplier weapon.
Originally Posted by Odlus
e.g. Scimi (18-20 threat, x2 multiplier) does 22 units of damage per 20 swings (19+3)More powerful named weapons have different more potent crit profiles... so later you will be looking at a range of possibilities.
Longsword does (19-20 threat, x2 multipier) does 21 units per 20 swings (19+2)
In contrast a Gaxe (20/x3) does 22 units (19+3)
Khopesh, which has a 19-20 threat AND a x3 multipier comes out with 23 units of damage.
A minor consideration is weapon base damage: D6 ona scimi and D8 on a longsword. works out to about 1 per swing in favour of the longsword.
But then consider each unit of damage includes...
- The weapon bonus (up to +8 or more at Epic levels)
- Your str bonus (or other stat if you're being all enhancey, and x1.5 for 2-handers)
- +5 or more from Power Attack Feat
- Various other damage bonuses (e.g. up to +8 (or more?) from Deadly items, + several from various enhancements... etc.)
- Bursting weapon effects on the crit hits (more for scimi)
Those extra "units" of damage become more and more pronounced the more powerful you become.
There might be other considerations that sway your weapon choice (and be aware that currently "to-hit" is not a major consideration), but in terms of straight weapon damage a wide crit range is good, a high multiplier is good, and some of both is better still... for pure damage.
Ultimately, if you put together a good toon, you'll be able to hit your enemies with a cursed club and still rock the quest. Play it out and see what you like best.