The AOpen AX64 Pro utilizes the VIA Apollo Pro 133A chipset, which consists of the VT82C694X North Bridge Controller and the newer VT82C686A South Bridge Controller. This North Bridge chipset is standard issue for any Apollo Pro 133A motherboard, but the VT82C686A South Bridge is a more recent addition from VIA and is also the default South Bridge option on the KX133 chipset. The Apollo Pro 133A allows the AX64 Pro to support AGP 4X, a true 133 FSB and PC133 SDRAM along with ATA-66 data transfers. The VT82C686A South Bridge offers additional features such as quad USB ports, AC97 audio and MC 97 modem options, as well as improved hardware monitoring capabilities and compatibility.