“For more complex requests that require more computational capacity, Apple Intelligence can use Private Cloud Compute, which extends the privacy and security of your Apple products like iPhone into the cloud to unlock even more intelligence. Private Cloud Compute uses larger, server-based models powered by Apple silicon.“
https://support.apple.com/en-gb/guide/iphone/iphe3f499e0e/io...:
“For more complex requests that require more computational capacity, Apple Intelligence can use Private Cloud Compute, which extends the privacy and security of your Apple products like iPhone into the cloud to unlock even more intelligence. Private Cloud Compute uses larger, server-based models powered by Apple silicon.“