Some games have a 60 Hz mode. This can be used by TV sets that can display images in 60 Hz.

If the television has an imaging frequency of 60 Hz, a smoother screen image with less flickering can be achieved with games that use 60 frames per second.

For this we recommend the Nintendo RGB Cable.

When a game supporting 60 Hz is started for the first time, a selection screen appears. You can now choose either 50 Hz or 60 Hz.
If you select 50 Hz, the selection screen is not shown again in subsequent startups as the GameCube 'remembers' this setting. However, the selection screen can be accessed at any time by holding down the B button during the startup.
If you select 60 Hz, the selection screen is always shown with this game. This avoids having to access the selection screen first when playing on a 50 Hz TV.