3DNow! is an extension to the x86 instruction set developed by Advanced Micro Devices (AMD). It adds single instruction multiple data (SIMD) instructions to the base x86 instruction set, enabling it to perform simple vector processing, which improves the performance of many graphic-intensive applications. The first microprocessor to implement 3DNow! was the AMD K6-2, which was introduced in 1998. When the application was appropriate this raised the speed by about 2-4 times. However the instruction set never gained much popularity, and AMD announced on August 2010 that support for 3DNow! will be dropped in future AMD processors, except for two instructions.

Read more about 3DNow!:  History, Advantages and Disadvantages, Processors Supporting 3DNow!