Specifications, 802.11ax backward compatible with the difference is that 802.11ac, take-all 2.4GHz, and 5GHz, of which 5GHz design maximum rate is 4.8Gbps. 802.11ac supports up to 8 devices, while ax supports up to 256 devices concurrently with Wi-Fi connectivity, providing a single-device peak rate of nearly 40% faster than the previous generation. Intel’s 802.11ax chip is based on the draft 802.11 2.0 802.11 standard and is optimized for Draft 1.0 devices for better interoperability with multi-standard devices.
Reference: Intel