Hi cinema4d, there is not currently any option to turn off curve antialiasing and make a jaggedy curve display instead...

I don't often hear about any problem with the curve display appearance, are you on a particularly low resolution display or something like that?

Or are you looking for a performance increase? If that's the case, try the v3 beta release, that uses multi-core processing for the display which can help improve that area. Also try turning off the hidden-line display (under View > Display hidden lines).

- Michael