Pros: It doesn't fit your regular PCI express slot.

Cons: It doesn't fit my regular PCI express slot. Bought 3 and return charged me restock fee and shipping back that costs me more than the cost of the cards to newegg.com. Even though I don't use it yet. Called Sinus company for over 10 times. None picked up the phones. Bad company support.

Pros: HD Tune Pro 4.61 Read Benchmark results using a MX200 M.2 SSD:

Windows 7 Intel M.2: 524.4 MB/s
Windows 7 USB 3.0: 282 MB/s
Windows 7 USB 3.0 with Boost: 312.1 MB/s
Windows 8.1 USB 3.0: 343 MB/s
Windows 7 PCIE 2.0 x16 Sunix USB2312 with USB 3.1: 334.5 MB/s
Windows 8.1 PCIE 3.0 x16 Sunix USB2312 with USB 3.1: 419.3 MB/s

Cons: Doesn't reach USB 3.1 theoretical max speeds.

Other Thoughts: A couple of things to note before I get started.

USB 3.0 bandwidth is 5 Gigabits per second (Gbps). To convert that to Megabytes per second (MB) is 128 × dGb = dMB. Therefore, USB 3.0 speeds have a theoretical max full duplex speed of 640 MB/s. However, since USB uses 8b/10b line code, turning eight-bit symbols into ten-bit ones, it incurs a 20% bandwidth hit. Thus, you'll see peak throughput of 512 MB/s. However, something causes slowdowns up to 45.5% or more, not just 20%, and no one really has specified why that is. That means you could see USB 3.0 flash drives or SSD's connected via USB 3.0 reach speeds close to 348.8 MB/s for sequential reads and writes, but no faster than that.

USB 3.1 bandwidth is 10 Gbps, twice as much bandwidth as USB 3.0, which equates to 1,280 MB/s theoretical speeds. Encoding is 128b/132b, so instead of a 20% bandwidth hit, it's only 3%. Nice! Thus, you'll see peak throughput of 1,241.6 MB/s? That means you could see USB 3.1 SSD's connected via USB 3.1 reach speeds close to 676.62 MB/s (factoring in the 45.5% bandwidth hit theory of mine). Sounds crazy, right?

Unfortunately, we are not going to hit that mark with the Sunix USB2312. Here's why.

The Sunix USB2312 supports PCIe 2.0 x2. Since a single PCIe 2.0 lane supports 512 MB/s, multiply that by two, and that's 1,024 MB/s. However, we run into the same 20% bandwidth hit, so, at best, that's 819.2 MB/s. That means you could see USB 3.1 SSD's connected via USB 3.1 reach speeds up to 446.46.6 MB/s (again, factoring in the 45.5% bandwidth hit theory), but no faster.

With USB 3.0 on Windows 8.1, I've been able to hit around ~343 MB/s. With USB 3.0 on Windows 7, it seems to top out at ~282 MB/s. However, when I'm able to use an ASUS board with USB 3.0 Boost, and enabling UASP, I hit around ~312.1 MB/s.

Using the Sunix USB2312 on Windows 8 with a PCIE 3.0 x16 slot, I get ~419.3 MB/s. On Windows 7 with a PCIE 2.0 X16 slot, I get ~334.5 MB/s. Interestingly enough, the Sunix USB2312 actually seems to support PCIE 3.0, even though the specs doesn't mention it does.

I'll probably play around with this some more in the future. The Sunix USB2312 is definitely nice to have, and it does provide the fastest USB Sequential Read speeds, but it's still not better than using a M.2 or SATA 6G connection. There's just too many known and unknown bandwidth hits preventing USB 3.1 from reaching it's peak theoretical potential.

However, it is nice to have something like this on an older x58 system to get 334.5 MB/s, although I was surprised that on Windows 8.1 using PCIE 3.0, I was able to get up to 419.3 MB/s. I'll need to do another test with Windows 7 and PCIE 3.0 x 16 to see if I get the same numbers. It may just be that Windows 8.1 handles USB 3.0 and USB 3.1 protocols a bit better.

Pros: Sunix usb2312 worked exactly as advertised and win-8.1 loaded the drivers automatically out of the box

Cons: None

Other Thoughts: Plugged the usb2312 card into a spare pci-E x4 slot in a 2009-Lenovo D20 that has legacy bios, sata-II, usb-2.0 mother board. The reason I added this Sunix usb-3.1 card is that the native usb-2.0 on the workstation was to slow when connecting to usb-3.0 capable external-HDDs (wd-myPassport and wd-MyBook 4TB). Previously, I have upgraded the D20 to win-8.1 and added an intel-730 480GB SSD. I have no way to test the full capability of the usb2312 card but after moving around 3TB of data, using external HDDs, the Win-8.1 copy window lists peak rate of approx. 123MB/s for large sequential image files and drops to between 43-60 MB/s for random files. These rates are close to HDD max transfer rates that have been documented in online-test reports. This setup used the MyBook connected directly to the usb2312 card and the MyPassport drive connected to a usb-3.0 hub (built into a Dell-U2413 monitor) that had its hub-source connected to the usb2312 card. Additionally, I had to disable McAfee Auto-scan since it caused the estimated rate to be cut in half. One other note on reported data-rate is that it appears win-8.1 spawns a "COM Surrogate" task to handle the copy through the usb-card. Using task manager the Com-Surrogate task reported a rate the was double (peaked to about 240MB/s) compared to the windows copy pop-up estimate. The box included one extra small bracket and a cd with drivers. I did not need to use the provided drivers since win-8.1 finds the correct driver (eXtensible Host Controller) for the Asmedia ASM1142. From the literature if you run Win-7 you will need to use the drivers provided on the cd. The main selling point for me was it used two pci-E channels (x2) and future compatiblity with Win-10. Very pleased with my purchase.