USB high speed decode and trigger doesn't work on 3000T. See up thread starting at post 2786 on page 112. Turns out there was a marketing/technical miscommunication.
LS and FS works.
Edit: even if HS did work, you'd need a 1GHz+ bandwidth scope. It does work on the 4000A and 6000X but they have hardware to support HS that the 3000T doesn't.
Looks like only the 1 GHz and 1.5 GHz 4000 series have the extra FPGA (U2303) and a few other IC's. Good thing I never had the chance to try modding a 4000 series to 1 or 1.5 GHz. It would probably be unhappy without the extra parts.
Presumably that means that certain 4000A bandwidth upgrades are RTB?
Edit: I guess so.
Yes, it should be the same as the 3000a/3000t series more or less.
-100/200 MHz
-350/500 MHz
-1 GHz
-1.5 GHz
If you look on the Keysight parts site you can just see the added chips in the tiny pics on the 1 and 1.5 GHz models.
Like the 3000t series I believe all 4000 series use the same base PCB. The 3000A used an updated PCB for the 1 GHz model.
A lower model 4000 should still be possible to upgrade to 1.5 GHz as a crazy DIY project but adding BGA into the mix lowers my "excitement" level. If I was to take on such a project I'd want to be extremely confident it was going to work when done.