The iPhone 8 doesn't support 20 fast charges. The Apple 8 uses fast charging technology, but supports a maximum of 18W of fast charging power. The Apple 8's official accessory comes with an 18W USB-C charger for faster charging speeds. While there are some third-party chargers that claim to support 20W fast charging, the Apple 8 itself does not support this power standard. Therefore, there is no additional advantage to using a 20W fast charger for the Apple 8.
Supported. However, according to the actual measurement, the highest charging power of Apple iPhone 8 can reach 19.49W, but the charging power remains at about 15W after stabilization;