Here are the specs for all of Ampeg's 4x10 cabinets :
PF-410HLF 800W 101dB 55-17K
PN-410HLF 850W 98dB 38-10K
SVT-410HLF 500W 98dB 48-18K (-3dB)
SVT-410HE 500W 98dB 60-18K (-3dB)
The numbers are power capacity, sensitivity, and frequency response.
You can see that the PF-410HLF is a more sensitive cabinet than the others and is not tuned to go as low. It also can handle quite a bit of power.