In August we took an early look at the ASUS P7P55D Premium motherboard, a P55 chipset offering that supports the new Intel Lynnfield processors under the Core i7/i5 brands. You might remember that ALL of the early P55 motherboards were going to support SATA 6G but the feature was suddenly pulled on almost every board due to mysterious performance issues. The P7P55D Premium was one of the only boards that retained the feature thanks to some additional hardware used by ASUS engineers.

Previous SATA 6G implementations used the Marvell 9123 chip that interfaced with the P55 chipset through a single PCIe 1.0 x1 lane - a connection that only had a 250 MB/s data rate. That data rate is already lower than the 300 MB/s rated specs on SATA-II and is obviously much less than the 600 MB/s rated on the SATA 6G standard. But because the Marvell 9123 could only support a connection of a SINGLE PCIe x1 lane, and because the P55 chipset only offers PCIe 1.0 connections, there was nothing motherboard vendors could do with the hardware provided.

The answer ASUS came up with involved a new chip: the PEX PLX8613 PCIe bridge chip. The PLX8613 allowed the Marvell 9123 to connect to it via a single PCIe 2.0 x1 lane (2.0 being the key here) for a maximum bandwidth of 500 MB/s. That is still not has high as the 600 MB/s limit of SATA 6G itself but is definitely a boost over the 250 MB/s mentioned above. The PLX chip then connects to the P55 chipset via x4 lanes of PCIe 1.0 that provide as much as a 1 GB/s of bandwidth; more than enough to cover the 500 MB/s coming from the Marvell 9123.

Read the entire article in PC Perspective.