I assume that this depends on your computer/GPU/GPU driver.
I have used Konsole for many years and I have used kitty for about 2 years in 2024/2025, then I have switched to ghostty around the beginning of 2026.
At least in my computers (with NVIDIA GPUs and Gentoo Linux), kitty was many times faster than Konsole and Ghostty even faster.
Moreover, in the now somewhat distant past when I was still using Konsole, it did not have some font rendering features that I desired, but that might have been solved meanwhile.
A reason why the terminal emulator speed is important for me is that I frequently compile big software projects and I find it unacceptable for a compilation to be slowed down by the low speed at which the compiler output is displayed on the terminal window, which happened frequently with all terminal emulators older than kitty and ghostty (I have always used CPUs with enough cores so that compilation itself is very fast, so the older terminal emulators become the bottleneck).
Because I run in parallel other programs and I want to interact with their windows, which would be much too cumbersome if I needed to switch between a virtual console and the GUI desktop forth and back any time when I want to watch the compiler output.
> A reason why the terminal emulator speed is important for me is that I frequently compile big software projects and I find it unacceptable for a compilation to be slowed down by the low speed at which the compiler output is displayed on the terminal window
I’m strongly skeptical of this as pty are character devices and buffered. Programs and terminal are very loosely connected.
Compiling any big software project produces far more text output than can be stored in any pty buffers.
There are a few big projects that redirect the compiler output and attempt to print only one line per output file, so when all goes well there is much less output text, but with those it is usually more difficult to debug failures.
> There are a few big projects that redirect the compiler output and attempt to print only one line per output file, so when all goes well there is much less output text, but with those it is usually more difficult to debug failures.
Why? If you use something like tee(1), you can get the full log in a file and then filter line according to what you want.
> Compiling any big software project produces far more text output than can be stored in any pty buffers.
The reason of my skepticism is that, according to your statement, reading a source file, then writing the compiled object file is way faster than a few printf through a kernel object in memory. Even for the terminal consuming the characters, parsing, and displaying the lines should not be a computation hog for most terminals
I have used Konsole for many years and I have used kitty for about 2 years in 2024/2025, then I have switched to ghostty around the beginning of 2026.
At least in my computers (with NVIDIA GPUs and Gentoo Linux), kitty was many times faster than Konsole and Ghostty even faster.
Moreover, in the now somewhat distant past when I was still using Konsole, it did not have some font rendering features that I desired, but that might have been solved meanwhile.
A reason why the terminal emulator speed is important for me is that I frequently compile big software projects and I find it unacceptable for a compilation to be slowed down by the low speed at which the compiler output is displayed on the terminal window, which happened frequently with all terminal emulators older than kitty and ghostty (I have always used CPUs with enough cores so that compilation itself is very fast, so the older terminal emulators become the bottleneck).