If you're using Linux, I'd advise you to use a fast terminal like Terminology; it even has GPU acceleration, but I doubt you'd need that. The only one that comes close on CPU-rendering speed is urxvt.
Meh, waste is relative. I run KDE programs, Gnome programs, and a couple of other random hodgepodge things at my personal whimsy, and I'm still only using 2.5GB of the 8 on my system for non-cache work, and over a third of that is just Firefox. I've got 3.5GB literally sitting empty, according to free. I can't even fill the caches. Running another set of depedencies to get me a noticeably better terminal emulator would cost me virtually nothing real.
Of course if you're in difference circumstances the answer changes. But there's no particular virtue in using a worse terminal so that more of your RAM sits there with lots of 0s in it.
Well, fwiw my local Debian Jessie claimed terminology along with dependencies (that weren't already installed) would claim 24MB. Pretty steep for a terminal. I tried opening one each of Terminology and Sakura[s] -- and as far as I can tell, running:
i=0;while true; do echo $i;i=$((i+1));done
is, if anything, slower in Terminology. Big caveat: I've just installed kernel 4.1.6 and while I've recompiled/installed the proprietary fglrx AMD driver, I'm not entirely convinced most OpenGL apps work as they should.
This terminal emulator is also a file browser and media center, so you can save space by removing your old ones of those ;)
(tyls is ls with thumbnails, and tycat is like cat except that if you try and cat a movie file to stdout it will display a video player instead of raw bytes)
I checked it out but couldn't figure out how to add my own color schemes? I'd preferably be able to use base16 flat https://chriskempson.github.io/base16/#flat however I can't even find a way to manually add color values.