Thats normal, if you overclock your going to have to have a higher vCore and other voltage settings along with overclocking the ram to the CPU.
I think the issue comes from the memory timings
for some reason it gets unstable whenever i increase the multiplier from 18.5 stock ratio. but one thing i dont understand is why my ram gets unstable even tho i'm not increasing the fsb ?? andd i really need help with setting the memory timings .