The only Rihanna albums that "4" did not outsell are GGGB & Loud. That's 5 out of 7 that got outsold by Beyonce's lowest selling album. Also, "4" first week sales were Beyonce's lowest yet bigger than all 7 of Rihanna's albums. We're talking US here.
It's interesting to me that 1.4m would be considered a hit era for Rihanna yet it was considered a flop for Beyonce. Rihanna's last couple of albums did not even reach 1.4m. It says a lot about the stature that people hold them to.
