Since we are so far off topic, I guess it's okay for me to ask an incidental question. While all this conversation is quite interesting and instructive, I'm curious how many people actually use or need bandwidth or sampling beyond 100 MHz and 312.5 S/s?
This is a very good question.
Even at 100Mhz the probing method and all those little cables on your breadboard will dominate any measurement and you need knowledge/experience to interpret what's on the screen.
Presumably, anyone working in comms, but who else? My thought process when buying the DHO800 was that even with 4 channels operating, I still have enough sampling to adequately cover the 100 MHz capability of the scope with the 150 MHz probes being well clear of having any attenuation effect at 100 MHz.
You have to be slightly careful here because the measured bandwidth of the Rigols is much higher than what the label says.
In reality the "70Mhz" model has 125Mhz bandwidth and the "100Mhz" model has 200Mhz bandwidth.
The probes have also been tested and are good for both.
My $0.02:
You could easily argue that "125Mhz" is the optimum configuration for a DHO800
and that it's as much as a hobbyist needs.
I wouldn't disagree.
As noted above: Probing dominates, even at these "low" frequencies.
eg. The difference between "probes" and "springs" is
huge and I hardly ever use the springs
(they're a pain in the ass).
I admit I usually have my DHO804 set to "200Mhz" because ... well ... I'm not sure. It's a head thing, I don't believe there's a practical difference for me in my "Arduino" work. The difference on screen is
tiny and mostly swamped by probing (see above).
I'm not saying that
nobody needs the extra 75MHz but you have to be into coax cables and 50 Ohm terminators to take advantage of it. If that's your case then fine. People who poke handheld probes at circuits? Not so much.
(I also think "200Mhz" is a very arbitrary number - why does no Siglent owner ever need 300Mhz?)