The Apple M1 is a System on a Chip (SoC) from Apple that is found in the late 2020 MacBook Air, MacBook Pro 13, and Mac Mini. It offers 8 cores divided in four performance cores and four power-efficiency cores. The big cores offer 192 KB instruction cache, 128 KB data cache, and 12 MB shared L2 cache. According to Apple the performance of these cores should be better than anything on the market (in late 2020). The four efficiency cores are a lot smaller and offer only 128 KB instruction cache, 64 KB data cache, and 4 MB shared cache. The efficiency cores (E cluster) clock with 600 - 2064 MHz, the performance cores (P cluster) with 600 - 3204 MHz.
The M1 is available in two TDP variants, a passive cooled 10 Watt variant for the MacBook Air and an active cooled faster variant for the MacBook Pro 13 and Mac Mini. Those should offer a better-sustained performance according to Apple.
The integrated graphics card in the M1 offers 8 cores (7 cores in the entry MacBook Air) and a peak performance of 2.6 teraflops. Apple claims that it is faster than any other iGPU at the time of announcement.
Furthermore, the SoC integrates a fast 16 core neural engine with a peak performance of 11 TOPS (for AI hardware acceleration), a secure enclave (e.g., for encryption), a unified memory architecture, Thunderbolt / USB 4 controller, an ISP, and media de- and encoders.