This study will evaluate the safety, efficacy, and tolerability of a regimen containing elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (Stribild®; E/C/F/TDF) fixed-dose combination (FDC) versus ritonavir (RTV)-boosted atazanavir (ATV) plus emtricitabine/tenofovir disoproxil fumarate (Truvada®; FTC/TDF) in HIV-1 infected, antiretroviral treatment-naive adult women.