Most older terminal emulators tends to do fairly well. E.g. on Linux, rxvt tends to be one of the fastest. Many older terminals tends to do well not least because many older terminals implements jump-scrolling properly (scroll multiple lines at a time before updating the screen if the rendering doesn't keep up) because there are even escape codes to turn that on/off.
There's a weird "bathtub curve" when it comes to terminal speed where the oldest tends to be well optimised in terms of tricks to minimise rendering, the newest all tend to concern themselves very much with rendering smart, but often miss the old-school tricks, and quite a few of the ones in the middle are just really naive about everything.
There's a weird "bathtub curve" when it comes to terminal speed where the oldest tends to be well optimised in terms of tricks to minimise rendering, the newest all tend to concern themselves very much with rendering smart, but often miss the old-school tricks, and quite a few of the ones in the middle are just really naive about everything.