Oil-filled shock absorbers

Oil-filled shock absorbers have normal air inside.
Oil-filled shock absorbers are good at low speeds and it fails at high speed movement.

Gas-filled shock absorbers

Pressurized Nitrogen Gas replace the normal air in a conventional oil-filled shock absorber to reduce the aeration or foaming. Gas-filled is a faster recovery shock absorber.

Theoretically, gas-filled starts from where oil-filled fails. Gas-filled technology is used by all modern manufacturers. as the vehicles are designed to go at high speed.