Regardless of what steel I use, I (or my heat treater) will heat-treat to 48 Rc. This is accomplished by adjusting the tempering temperature. I'm not a metallurgist, but my understanding is that the 80CRV2 will harden more consistently/thoroughly than the 1075, with less distortion/warp. The same can be said when comparing any oil-hardening steel to any water-hardening steel. I don't have a direct answer to your question, but I have every reason to believe that 80CRV2 will be as good as 1075 in an impact test; perhaps better. In the beginning I performed these types of tests, now I rely on customer feedback. For example, I went from 50 Rc to 48 Rc after reports of several tips breaking. I also went from a blunt grind to a more acute grind after complaints of knives not sticking well. Its a constant process of improvement, optimization and compromise.