Speed of varchar vs. char in indices

Hello,

I have a table:

CREATE TABLE pge (
  pge_id      SERIAL,
  pge_path    CHAR(255) CONSTRAINT ak_pge_path UNIQUE,
  PRIMARY KEY (pge_id)
);

From other tables I now reference pge_id as well as pge_path. Somewhere I
have read that indices on CHAR are faster than those on VARCHAR.

Any remarks?

TIA
Mirko