3DNow! is a deprecated 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 vector processing of floating-point vector operations using vector registers, which improves the performance of many graphics-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! would be dropped in future AMD processors, except for two instructions (the PREFETCH and PREFETCHW instructions). These two instructions are also available in Bay-Trail Intel processors.