The various DSL methods use error correction based on the interleaving of data packets: interleaving or time interleaving. Interleaving in turn causes longer ping times. These are counterproductive for online games because, like Internet telephony, they require short action times.
To reduce ping times, Fastpath is a standardized transmission technique that eliminates interleaving and thus shortens ping times. This also means that Fastpath does without error correction, but shortens ping times. DSL techniques work with either interleaving or fastpath.
Fastpath has the disadvantage that packet losses could increase slightly, but this depends on the quality of the access lines and the access network.