Lazarus version, fpc version ?
Lazarus 1.8 is on the way. It will have improved handling of high screen resolutions. Or try the current trunk version to see it right now.
Since you have Laz 1.6.4 you can follow these instructions: http://wiki.freepascal.org/Installing_Lazarus#Installing_from_source_starting_with_a_stable_release.Or you use fpcupdeluxe (https://github.com/newpascal/fpcupdeluxe/releases/tag/1.4.0c).