How bad is a high-res landscape for performance?

Hi! I am currently detailing a lot of my landscape but have found that I’m ending up with a lot of ugly triangles in some spots where I want some neat ledges and cracks.
I already have a resolution of 127x127 per component for my landscape, so I would have to up it to 255x255 in order to improve it.

Are landscapes decently efficient or should I avoid increasing the resolution at all costs?

the landscape system is pretty robust, on one of my levels my arena is 256x256 component size 1532 components and resolution of 8416x13771. total tri count is 199,236,600 and takes up 3.219GB of data. by its self, the landscape sits at around 2ms render time with everything in view.