When the 750 “Irongate” made its way onto the market, AGP 4x was still Intel's baby and had not yet been introduced. AMD has rectified this with the 760 however, and the feature has finally been implemented. The AGP slot is compatible with the version 2.0 specifications and can run in 4x, 2x or even 1x mode for those with older video adapters. Side band addressing is supported in addition to fast writes, which we were able to enable with a special version of NVIDIA's Detonator 3 driver (6.27 for Windows 98). Since AMD neglected to include Windows 2000 video drivers, we used version 6.31, and PowerStrip reported AGP4x, SBA, and fast writes were all enabled. We have yet to see a significant performance increase due to the increased bandwidth of AGP 4x, but by adding this feature, AMD has effectively matched the graphics potential of the VIA KT133 chipset.

Enhancements have also been made to the PCI bus controller present on the 761 North Bridge. Whereas the 750 (and VIA's KX/KT133) boasts up to five bus mastering devices, the 760 supports a maximum of seven. Previously, to support more than five PCI slots would require either an arbiter chip or the additional devices would not serve as bus masters. Given the trend towards six PCI slots on a motherboard, this should simplify PCI implementations for those manufacturers who have been using arbiter chips for additional PCI connectivity.

The 766 ViperPlus is the successor to AMD's 756 South Bridge that debuted with the 750 chipset. A few changes have been made to the 766 to bring it up to date with solutions from both Intel and VIA.

AMD's first enhancement comes in the form of DMA/100 support. Both primary and secondary channels are compatible with PIO modes 0-4, DMA mode-2 supporting up to 66MB/s bursts, and up to 100MB/s supporting the DMA-100 interface. Unfortunately it appears as though the drivers still need some work, as we were unable to get DMA mode functioning under Windows 2000.

Like the 750, AMD's 760 chipset can maintain four 1.1-compliant USB devices (that means no USB 2.0 support). Legacy PS/2 keyboard and mouse support, of course is standard. ACPI 1.0 and APM 1.2 compliancy means that systems with a 760-equipped motherboard will be able to enter soft-off and power-on suspend with hardware automatic wakeup.