I think you didn't say what you meant to say. But 4 SATA HDDs *can* saturate a 1 Gb link (note not 1 GB but 1Gb - there is a difference) and so 10Gb will result in a substantial performance improvement. I doubt that 4 SATA HDDs can saturate a *two* 10Gb links, but that is not the point. Its useful to have a backup link in case something goes wrong (which happens often enough in my experience). At this performance level, most users will want dual links. And most users of this product will access it from multiple clients, in which case the two 10Gb links will provide a performance boost also.