The purpose of this trial is to compare the effectiveness, safety and tolerability of TMC278 given at a dose of 25 mg once daily versus efavirenz (EFV) at a dose of 600 mg once daily, when combined with a fixed background regimen consisting of emtricitabine (FTC) + tenofovir disoproxil fumarate (TDF), in HIV-1 infected patients who have not yet taken any anti-HIV drugs. The following evaluations will be done: antiviral activity, immunologic changes, and viral geno-/phenotype evolution, relationship of Pharmacokinetics (PK) and PK/Pharmacodynamics, medical resource utilization and treatment adherence.