This is what I have determined so far: 1. this problem is common with this chipset and drivers as verified by the many posts RE this issue. 1a. It occurs with v1.90, 2.10, & 4.00 of the drivers - actually, it may not have occurred for me on 1.90. 2. it does not depend on what MB it is connected to. I now have an ASUS P8Z77V-LE Plus, but it occurred on my Gigabyte P43-ES3G 3. It occurs on Etron USB3 chipsets also, but the VL800 is more prolific. 4. For the Via VL800 (which I have in a front panel 3x USB3/2 + card reader implementation), if I run DPCLatency I see a periodic (~10sec) latency of about 1800us which is OVER the MS DPC service time specification of 1000us. That latency is totally attributable to this device. 5. The system hang is totally random. 6. I have not observed a hang when a browser was not running. 7. It happens with both IE and FF browsers. 8. It has not hung if I run with a device in a USB3 port or a card in a slot. My conclusion is that it is a driver issue where the driver never completes the servicing of the DPC so the PC 'locks up'. The main problem being that my implementation is not from a company I can discuss it with and VIA won't talk to end users. Therefore, it is not likely to be resolved.