AES is used to speed up encryption and decryption.
SSE is used to speed up multimedia tasks such as editing an image or adjusting audio volume. Each new version contains new instructions and improvements.
AVX is used to help speed up calculations in multimedia, scientific and financial apps, as well as improving Linux RAID software performance.
MMX is used to speed up tasks such as adjusting the contrast of an image or adjusting volume.
F16C is used to speed up tasks such as adjusting the contrast of an image or adjusting volume.
Multithreading technology (such as Intel's Hyperthreading or AMD's Simultaneous Multithreading) provides increased performance by splitting each of the processor's physical cores into virtual cores, also known as threads. This way, each core can run two instruction streams at once.