View source for Strain-Based Psionics (3.5e Variant Rule)

==== Strain Tolerance ====
You strain tolerance is equal to your primary manifestation ability score (again, the actual score, not the modifier) plus half your level(s) in psionic classes and classes that add to your manifester level. Your strain-determining ability score is equal to the one that would determine your bonus power points per day in the old system.

I'm not yet changing this on a per-class basis because [[SRD:Wilder|wilders]] are a one-trick pony class reminiscent of a NPC class and [[SRD:Psychic Warrior|psychic warriors]] are pretty dull. So yeah, all the little psychics of the world have the same strain tolerance. Equality, Yeah!™