modems in the 90s would still negotiate 300 baud connections depending on how good the phone connection was, which could depend on the weather. I think there also needs to be a full duplex loop from the terminal emulator to the unix host and back for the character to show up on the screen. And consider that the both the PC that the emulator was running on was a 90s PC, and the web server I think was a shared host at the ISP. Some vi commands also would trigger a lot of screen update action. It was very easy to type far ahead of what was on the screen. If I lost track of what I had typed, I would have to stand up and walk away from the keyboard for a sec to let the screen catch up.
I started using modems in the late 80's. My first one was 1200 baud. Never once did a modem negotiate 300 baud on its own, even in the worst conditions. Were you connecting through a tin-can with string?
Terminal emulators are not CPU intensive applications. I ran one on an Apple II (8-bit, 1 mhz) and it could keep up with at least 2400 baud. If you were refreshing the screen with vi, I could see it being slow.
