No other changes in the antiretroviral regimen will be allowed for the first 12 weeks. Thereafter, the investigator may change background ARVs based on the results of the screening resistance test. No new class of antiretrovirals will be allowed to be added through 48 weeks. Subjects will be monitored closely over 48 weeks with careful assessment of CD4 profile, viral loads and lipid profiles as well as drug resistance and replication capacity. Stopping rules will be implemented based on CD4 and viral load profile to ensure subject safety. The objective of this study is to determine whether protease inhibitor regimens that have less of an adverse impact on lipid profiles can maintain a stable CD4 profile compared to standard ritonavir boosted PI regimens.