Direct displacement based design method, which has been presented by Priestley, is the newest performance design method of RC buildings recently noticed by many researchers. It refers to the seismic behavior of buildings and their performance during strong earthquakes. This method has a new point of view in comparison to the ordinary well-known forced based design method. This paper compares seismic behavior of RC buildings designed by two basically different design methods; DDBD method and the forced based method in the Iranian Code of Practice; Standard-2800 (the 3rd edition). For each design method, four RC Buildings: 4, 8, 12, and 16-story two dimensional special moment resisting frame are designed based on a specific design spectrum. Seismic performance of all buildings using the dynamic inelastic time history analysis is evaluated against two seven-member artificial records. The members of the first group are synthesized by SIMQKE1 and for the second group a new proposed (by authors) simple approach based on the Fourier transform modifies the real accelerograms. All members of the two groups have response spectra match to the specified design spectrum of the buildings. Extensive analysis shows that all buildings designed by DDBD have a strong and regular behavior and meet their performance criterion (2% drift ratio), while the buildings designed by Standard-2800 can not perform well such that they do not meet their performance criteria even with those designed based on.