SiS sent us earlier a PR with the official announcement for the Xabre 600, nothing new features-wise really other than faster clock speeds...

Silicon Integrated Systems Corp. today unveiled the latest generation of its Xabre graphics chipsets, the Xabre600. Built with 0.13-micron process technology, the Xabre600 not only inherits the superb features of Xabre400 to support 8X8 (AGP8X and DirectX8.1), but has become a super graphics engine with complete Pro 8X8 features delivered by a built-in hardware optimized Vertexlizer Engine.

Unfortunately the fancy names doesn't seem to do much for the cards, both TechReport and Hothardware have write ups showing relatively poor performance even when compared to NVIDIA's MXs.