A method for a fast full search motion estimation with SIMD merge instruction. The method of one embodiment comprises loading a first line of K data elements for a current macroblock. A first set of L data elements and a second set of L data elements for pixels in a search window are loaded. A shift right merge operation is performed on the first and second sets of data elements to generate a second line of K data elements. A first sum of absolute differences value between said first line and said second line is calculated. The first sum of absolute differences value is accumulated to a first total for a first reference macroblock.