なんでinterbase 6.5でググれば一発で出てくる話を確認しなきゃいけないんだ…ﾌﾞﾂﾌﾞﾂ

http://bdn.borland.com/article/0,1410,28107,00.html#Other_Changes
に
Past versions of InterBase have transmitted VARCHAR fields from the server
to the client padded to their full length with spaces. This could cause
performance problems on slow or heavily loaded networks. This behavior
has been changed so that only the actual data in the VARCHAR field is
transmitted.
とある。

和訳しろとかゆーなよ。