Swapped Airspy R2 to USB3 around 1:40 GMT last night. CPU usage increases by about 6%. This implies more messages. With 6:15 hours until the end of day collection period, I currently show 2454 planes and 447,269 messages. This seems to be somewhat higher than the usual Monday traffic at this time. It could be a random thing, but the cpu usage chart took a that 6% jump at the same time as the cable was moved to USB3. Also seeing higher 250+ m message counts, usually around 400 and today at 1637 so far.
Something is happening, just not enough info yet to see a definite trend. I will run a similar test with a Pi4 / FlightAware Blue receiver on USB2. Laying down a baseline now for a day or so and then changing to USB3. Might be interesting, might be nothing.
Now I need to add that pizza pie plate to the bottom of the antenna… See message #114 of Confused with ADS-B range