date1.Hours == date2.Hours &&
date1.Minutes == date2.Minutes

Int64 t1 = (Int64) TimeSpan.FromTicks(date1.Ticks).TotalMinutes;
        Int64 t2 = (Int64) TimeSpan.FromTicks(date2.Ticks).TotalMinutes;
        return t1 == t2;

date1.AddSeconds(-date1.Second);
date2.AddSeconds(-date2.Second);
TimeSpan.Compare(date1.TimeOfDay, date2.TimeOfDay);

var span1 = new TimeSpan(date1.Hour, date1.Minute, 0);
var span2 = new TimeSpan(date2.Hour, date2.Minute, 0);
var diff = TimeSpan.Compare(span1, span2);