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  • repoman27 - Monday, April 16, 2018 - link

    "...the aggregate bandwidth it supports is limited to 8 ~ 10 Gbps (depends on its implementation)..."

    Naw, due to 8b/10b encoding for PCIe 2.0 vs 128b/130b encoding for PCIe 3.0, the channel capacity is 8 Gbit/s or 7.877 Gbit/s. And we can probably assume that the three xHCI chips are connected as PCIe 2.0 x1, x1, and x2, so the ASM1142 would have an 8 Gbit/s connection.

    This is a confused and idiotic product. If your target market is people willing to spend $200+ for maximum bandwidth, then why didn't they go with a pair of ASM1142's? All of the ports would have then supported either 5 Gbit/s or 10 Gbit/s USB 3.1 operation. And I can't think of any USB Type-A thumb drives or devices with captive Type-A cables that would actually benefit from a 10 Gbit/s connection, so this is actually a reasonable scenario to go all-in on Type-C. The arbitrary mix of Type-A and Type-C is detrimental here; 2x Thunderbolt 3 and 4x USB 3.1 Type-C would have been better.

    Furthermore, at this price, all of the ports should support the latest USB Battery Charging and Power Delivery specs. Then the power brick could be USB Type-C as well. Heck, throw on a seventh Type-C port just for PD if you don't want to sacrifice any of the data ports for power.
  • joevt - Saturday, May 26, 2018 - link

    The ASM1142 can operate at PCIe 3.0 x1 (8 GT/s @ 128b/130b = 7.877 Gbps, 984.6 MB/s) or PCIe 2.0 x2 (5 GT/s @ 8b/10b = 8 Gbps, 1000 MB/s).

    USB 10 Gbps @ 128b/132b = 9.697 Gbps, 1212 MB/s). Flow control, packet framing and protocol overhead might reduce that to below even the max allowed by PCIe 3.0 x1?

    They could have used four ASM1142 (without using a PCIe switch) to provide 8 ports of USB 3.1 gen 2, but pairs of ports would be limited by the PCIe 3.0 x1 max (984 MB/s) and all ports would be limited to the Thunderbolt 3 max (2750 MB/s?). These limitations generally won't be a problem because all ports will likely not be used at the same time (unless some kind of USB raid is created?).
  • noblemo - Sunday, August 12, 2018 - link

    Aggregate bandwidth for the device is limited to 20 Gbps according to the manufacturer's website. I would like an adapter that provides 40 Gbps Thunderbolt 3 to 4-port x 10 Gbps USB 3.1 Gen 2. This StarTech unit could potentially work if the two Thunderbolt ports support USB-C 3.1-G2, but the 20 Gbps total data rate is disappointing.

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