Hi,
I have a product that consists of 2 USB devices, one USB1.1 camera and one USB2.0 streaming device. These two are connected on a hub. This hub is then connected to the computer. The chip on the streaming device is a cypress chip. Each data streamed contains data markers that are parsed on the end point. The data rate is approx 20MB/s. The data from the camera is streamed using directshow. The other USB device is streamed using QuickUSB asynchronously .
With older Intel processors (Core 2 duo) this set-up worked. On the desktop we could see data from both devices at the same time smoothly. The markers were intact. Then we tested on the newer Intel processers (i3, i5, i7). On these new computers, the data from the streaming device would be corrupted. The rate of data requests that would come back 'complete' is 1/20.
I'd suspected power issues, but both devices are powered properly, and just to rule it out we modified the hub so that it would be externally powered. Both devices would not use the power supplied by the usb hub but the external power. The results showed that external power did not improve condition.
If anyone has an idea on this, please let me know?