SuperSpeed USB - How much is it actually?

Question

I have seen a number of articles mentioning SuperSpeed IP sales and various performance numbers (only theoretical). I would like to use this platform to inform the users the actual speed achieved on USB 3.0 Development board by IP designers at SLS The core efficiency is dependent on a number of factors like 8b/10b encoding, packet structure and framing, link level flow control and protocol overhead. At 5Gbps signalling rate with 8b/10b encoding, the raw throughput is 500MBps. When link flow control, packet framing, and protocol overhead are considered, it is realistic for 400MBps or more to be delivered to an application. Various tests performed with SLS SuperSpeed USB core on GigaByte A75 Motherboard have indicated the performance ~2.1Gbps with mass storage interface and ~2.7Gbps with raw interface. Any other experiences with the speed/performance of SuperSpeed cores are most welcome! 
 Attachments: br_dbusb30_r2a_1.0.pdf br_usb30sf_1.1_1.3.pdf

DAB · Answer

The true data rate on any connection depends upon several things.

Protocol

Error detection and correction

Data buffering speed on both sides of the connection

Direct memory access

memory and cache speeds

software and firmware speeds

I could go on, but the main message I want to leave here is that you need to look at your entire system components before you can determine your best run time speeds. I have seen several 100 Mbps links that could only support about 10 Mbps after you threw in the above conditions.

Bottom line, build a nice timing simulation and check out the real capabilities of your system components, both hardware and software. If you just trust the specification sheets, you will end up with timing problems. I know, this was my specialty for a large number of years. I built my own system simulation software and helped different customers find a lot of hidden timing problems within their system.

Trust but verify.

DAB