AMD says their upcoming Hybrid CrossFire technology will offer fairly big performance boosts.
Low-end systems will benefit most, the firm says a Radeon HD 2400 and RS780 chipset working in Hybrid CrossFire will result in a 50 percent increase in 3DMark06.
Nvidia on the other hand is touting a ~40% boost in pairing up their MCP78 chipset with a mainstream discrete graphics card, ~20% boost with a performance card and ~5% boost with an enthusiast card.
AMD is also touting low power consumption of the RS780 chipset reaching only a mere ~1.2W on idle and has ability to shutdown the discrete graphics when GPU load is low. Other neat features that RS780 chipset support are DX10, HT 3.0, PCIe 2.0, UVD, HDMI/DVI/DP. Boards based on RS780 chipset will be available in Dec '07 or Jan '08.