Britney. She had had a peak from 1998-2004. The same thing cannot be said about Gaga.
Edit: And she once again had a peak from 2007-2009. Britney was everywhere whether she was at the of her game or at her lowest point of her game. Her meltdown alone is bigger than Miley
Gaga had the biggest peak after Britney, but Britney's peak....oh my goodness. It was HUGE! She singlehandedly changed EVERYTHING with ONE song and ONE music video! And she was on the news, on every magazine, everyone worshipped her. She has the biggest peak for a female pop star besides Madonna and it's no contest.
Having experienced both of their peaks, I would say Gaga's peak was more intense and all-consuming in terms of worldwide pop culture but Britney's peak lasted twice as long
So the answer is Gaga by a hair
Britney. She had had a peak from 1998-2004. The same thing cannot be said about Gaga.
Edit: And she once again had a peak from 2007-2009. Britney was everywhere whether she was at the of her game or at her lowest point of her game. Her meltdown alone is bigger than Miley
Congrats to Britney for selling albums when people actually bought albums
We all know by the time Britney peaked people actually bought albums, but she didn't need any trick to be as big as she was back in that time, unlike Gaga.