I have set a simple scene with sphere applied ornatrix hairs and vrayornatrix mod modiefer on the hairs and hairs rendering perfectly with cpu render but in gpu it only renders the view port count hairs from the option but not rendering hairs from the render count option.
When using the GPU, are you rendering in IPR mode? If so, that is common in IPR, since it will render whatever it's in the viewport. For IPR you have to set the viewport hair count to the same value as the render hair count.
