particle systems' physics heavily depends on framerate??

hi! we are making 2d game and i stumbled upon some strange behavior

when i made some particle systems in unity3d itself everything was looking right

when i made an application and started it on maximum settings, particles were behaving themselves like crazy. when i started at low settings and they were good

i'd found out that it depends on vsync setting (and FPS, as result).

now, without vsync FPS is 1100 (with vsync: 60)

may be even whole physics is changing, i haven't spotted that yet

so the question is: how to fix? i can't just turn off the very possibility to turn vsync on, because as i understand, when game will become more complicated, FPS will drop, and what? redo all particle systems? and tearing may appear, why do so?

from other hand i can't force VSYNC for next reasons:

intense difficulties with working in unity IDE itself (it runs game "preview" without vsync, also, in "scene" mode particles appear as they are without vsync on.)

also game will be playable at 30-50 FPS, how it will behave with forced vsync? it will turn it off and particles will start to behave weird again?

(no scripts were used in particle systems' gameobjects, just empty GameObject with system attached)

i'm not asking here, why unity3d can't vsync by multiplies of 60 tho. but it's pretty interesting to me too

p.s. pardon my english