AnandTech took the SiS 756 and compared it with other Socket 939 chipsets including NVIDIA's nForce4, ATI's Rx480 and ULi's 1695.
The SiS 756 is an upgrade to the SiS755FX chipset that we reviewed last December. Where the 755FX was PCI/AGP, the SiS 756 was to feature the PCI Express bus with PCIe graphics. The SiS 756 first appeared as Reference samples to reviewers many months ago, but the retail products have taken a long time to appear in the market. Our readers will likely advise us of other offerings, but almost 6 months after review samples, we could only find one production SiS 756 board, the ASRock 939S56-M, and even it is difficult to find. We also discovered that the ECS PF88, the ECS modular CPU board discussed in Editors Day 2005: A "NEW" ECS Looks to the Future, uses the SiS756 on the A9 add-on module for Socket 939. We could not find any other current production boards using the SiS 756 chipset.
Check out the full review of this chipset over at AnandTech.