Asus U3S6 SATA 6 & USB 3.0 Card Review

USB 3.0 Meets SATA 6
Unlike many daughter cards on the market today, the Asus U3S6 is not only a USB 3.0 card, but also a SATA 6Gb/s expansion "combo" board. This versatility coupled with its all black PCB does make for one sexy upgrade. For an expansion card, the Asus U3S6 is certainly a beefy package measuring a good 4.8 inches long. While it is longer then most, it still is only a single slot solution as all the controller chips are considered low power, with no bulky heatsinks required to keep them cool. One noteworthy feature, is while the card is long for a USB 3.0 adapter card (especially compared to an x1 like the Gigabyte GA-USB3 card) it still is a low profile card. You simply have to be able to source out a low profile bracket (which is not included) or do without a bracket all together to use it in a smaller footprint HTPC system (for example). This does make this card extremely versatile as many consumers wanting to upgrade a system to USB 3.0 are doing so becuase it will make transferring files to and from their HTPC all that much quicker!

From left to right, NEC USB 3.0 host silicon, PLX bridge chip, Marvell SE9123 chip.

The controller chips responsible for this versatility are the NEC D720200F for the dual external USB 3.0 ports and a Marvell SE9123 chip for the dual internal SATA 6Gb/s ports. All ports are of course backwards compatible with their earlier perspective standards. While it is unfortunate that the USB ports are external only and the SATA 6Gb/s ports are internal, this is a limitation of the controller chips and not an oversight on Asus's behalf. Both of these controller chips are rated for only two ports each and this is the most logical setup with such limited number of options available. Rounding out the features of this board and taking it from the merely ordinary to the extra-ordinary is the PLX bridge chip. This is the chip which allows the onboard controller chips to take advantage of more than 1 PCI Express 2.0 lane of bandwidth. This trifecta of chips is literally the same setup Asus use on their latest motherboards to offer USB 3.0 and SATA 6 to their customers; albeit with a higher markup then $30.

Asus U3S6 x4 compared with Gigabyte USB 3.0 x1 card. There are only two caveats to the Asus U3S6, one minor and one major. The minor one is universal to all adapter cards in that you will need to install the NEC USB 3.0 and Marvel SATA drivers before you can take advantage of the USB 3.0 and SATA 6Gb/s ports. This is an extremely minor issue, as the drivers are included on the accompanying CD. The major caveat to the Asus U3S6 is it does require a x4 PCI slot and not the more typical x1. In many cases, this means you are going to have to populate a 16x "graphics card" slot as your motherboard probably won't have any available x4 slots. The upside to providing 4 lanes for data throughput is that in theory any of the USB 3.0 (600MB/s) ports OR the SATA 6Gb/s (750MB/s) ports could theoretically saturate one PCI-E 500MB/s lane all by themselves and cause a performance bottleneck. In reality, it is doubtful any single device will be able to do this in the near future, but the ASUS U3S6 is more future proof then its x1 brethren because of this forward thinking interface.

On the positive side, the U3S6 does not require any external power sources. It can draw all the required power from the PCI-E slot. This is a very nice feature as having to plug in a Molex connector to an expansion card does detract from clean look many users want and more importantly can impede the air flow to the PCB's controller chips which they require to keep cool.