It depends on the load
Depends on which 45 and which 44 chambering you are talking about the load
.44 Magnum is the more powerful cartridge.
The longer case of the .44 Magnum holds more powder, and, even though the .44 is smaller in diameter, it tends to pack a heavier projectile, ranging from 240 to 350 grains, vs. the typical 165 to 235 grain projectiles used by the .45 ACP.
.44 Magnum
Of course a 45 is more powerful, but the 9mm has the advantage of speed and a larger chamber. If you only get one shot, pick 44. Multipule. Then pick 9mm
I'm not aware of a .45 Magnum. There is a .44 Magnum. The 44 magnum is typically a revolver round, very high power. The 45 ACP is typically used in semi-automatic pistols. The 45 ACP is not as powerful compared to the 44 magnum (mostly due to the amount of propellant in the 44 magnum compared to the 45 acp).
45. Leaves a bigger hole
44 out of 45 is 97.78%
44 is 97.78% of 45
LCM of 44 and 45 is 1980.
44 times 45=1,980