Prime Hiruzen would be 5 times stronger!
Old Hiruzen hasn't seen action in over 10 years. Plus his speed, Strength, stamina and Chakra have diminished by a lot. Enma, Anbu and Orochimaru have all noted this during the battle. Plus the fact he was able to hold off 2 Edo Hokages and Orochimaru is a testament to his strength. Imagine his prime!
Well considering he was able to fight against oro and the first and 2nd hokage by himself in his old age means in his prime when he was younger he could probly solo a whole nation lolz
from the way enma, oro, kabuto etc hyped his prime, i'd say prim hiruzen was 50x stronger than the one we saw... considering enma called his fighting pathetic