We have seen this.
First of all, you need more RAM in your PC. 512 is not enough capacity for streaming mode loads with all channels running and samples turned up. Your PC will run out of RAM and start grabbing pagefile and this makes it slow way down.
However, this may not be related to this issue. I have seen it on PCs with plenty of RAM but not on others. We are working to identify the issue.
Have you seen any data gaps in your captures?
For now, max that PC out on RAM. You need it anyway. See if that helps.
(The Picotologist) http://www.autonerdz.com
THE PicoScope Automotive Authority
In North America