What is the fastest wordpress hosting?

There is nothing like fastest hosting it depends on server configuration if using CDN/Cache/Memcached/Pagespeed Cache etc.

As WordPress is a PHP based package and it takes some time for PHP-FPM compiler to do its job and also depends on the server resource availability and disk I/O availability everything have a limit of bottleneck once it reached then you know what happens.

The fastest Wordpress hosting is available from hosting.uk and owned-networks.net. They are cheap and reliable around the clock.