Well, with old manual configuration of X11 and guessing some parameters I get sharper fonts with nv driver.
But with nv and vesa driver there is other problem: If I type a little fast for example in xterm, vi or emacs, characters get repeated many times likkkkkkkkke thiiiiiiis. I have never before experienced this behaviour with X. Is this normal? I tried in Device with Option "AccelMethod" "EXA" Option "MigrationHeuristic" "greedy" and at the end I had to put due to errors: Option "NoAccel" "1" Rodrigo