I've been looking for an extremely fast terminal emulator for many years. xterm has unfixed rendering bugs and is slower than molasses. I don't like urxvt's lack of memory management. st uses more memory than xterm (yep!).

Just saw Alacritty on HN and was determined to try it out.

What are your plans for older hardware? I'm currently using a couple of laptops from 2007-2008: a ThinkPad T43 and a ThinkPad T60. Unfortunately the Rust nightly you're currently using is broken on i686 (#126) so I can't test Alacritty on the T43, but it reported the error in the title on my T60 (which has a slightly better GPU, FWIW).

T43 specs:

OpenGL vendor string: X.Org R300 Project
OpenGL renderer string: Gallium 0.4 on ATI RV370
OpenGL version string: 2.1 Mesa 11.0.2
OpenGL shading language version string: 1.20

01:00.0 VGA compatible controller: AMD/ATI [Advanced Micro Devices, Inc.] RV370/M22 [Mobility Radeon X300]

T60 specs:

Extended renderer info (GLX_MESA_query_renderer):
    Vendor: X.Org R300 Project (0x1002)
    Device: ATI RV515 (0x7145)
    Version: 11.2.2
    Accelerated: yes
    Video memory: 128MB

01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV515/M54 [Mobility Radeon X1400]

Yep, I realize these are kind of the "oh wow" of GPU land :) but I'm genuinely wondering what the best approach would be to support GPUs like these - I've been pondering making my own terminal emulator for a little while (as well as a 2D engine too, actually), but have absolutely no knowledge of OpenGL, Vulkan, etc.

"It would be impossible" is completely understandable; "it would require a nontrivial architecture redesign" also wouldn't be too surprising.