AMD's next generation of graphics processors (GPUs) that will be branded under the HD 7000 series, are reported to be PCI-Express Generation 3 compliant. The desktop discrete graphics cards will feature PCI-Express 3.0 x16 bus interfaces, and will be fully backwards-compatible with older versions of the bus, including Gen 1 and Gen 2. Motherboards sold today feature Gen 2 PCI-E slots, although some of the very latest motherboards launched by major vendors feature PCI-Express 3.0 slots.
The new bus doubles the bandwidth over PCI-E 2.0, with 1 GB/s of bandwidth per lane, per direction. PCI-Express 3.0 x16 would have 32 GB/s (256 Gbps) of bandwidth at its disposal, 16 GB/s per direction. AMD's next generation of GPUs, codenamed "Southern Islands" will be built on the new 28 nm process at TSMC, and will upscale VLIW4 stream processors. Some of the first PC platforms to fully support PCI-Express 3.0 will be Intel's Sandy Bridge-E. Whether AMD's GPUs have hit a bandwidth bottleneck with PCI-E Gen 2, or is AMD trying to just be standards-compliant, is a different question altogether.