Softcaps are dependent on your current level.
Nybling from Tamriel Foundry
at Veteran Level 5 in Cyrodil:
-1842 Max Magica was not Overcharged whereas 1918 Max Magica was overcharged.
- 88 Mana Regen was overcharged
-2440 Max Health was not ovecharged
-1120 Max Stamina not overcharged
-1661 Spell resistance not overcharged
- Spell crit can not be overcharged
Phaszius
at Veteral Level 10 in Cyrodil :
- Max Helth 2976 overcharged
- 2800 Max Health not overcharged
- Spell Resitance 1692 overcharged
- 78 Magica Recovery overcharged
- 52 Helth recovery overcharged
- 70 Stamina recovery not overcharged
- 95 Stamina recovery overcharged
Level 6 (not Veteran) in PVE:
-Max Health 456 overcharged
I will post if I find some more numbers. I am pretty sure I can give you the Lvl 20 Magica Bonus overcharge values for PVE and PVP after this weekend and maybe lvl 21 and 22 too
