HP5 is certainly grainier than Tri-x, but it's also sharper, atleast in 120 anyway. Tonality is a separate discussion. I've standardized on HP5 and Tri-x both in ID-11 1:1. HP5 pushed slightly in flat light and Tri-x shot at 250 in contrasty light. This works well for me. I don't worry much about grain. I, like Thomas prefer grain in the image.