Encumbrance affects only 4 things :
- chances to fizzle spells
- time to cast a spell
- effect (buff, debuff, damage, heal NOT visual) of a spell
- arrow damage : for each 10 archery encumbrance starting at 50, you do one less damage (0-49, no malus, 50-59 -1 dmg, 60-69 -2 etc.).

[Linked Image from w3.the-kgb.com][Linked Image from w3.the-kgb.com]