I recall we got it running pretty decently on an upper end 486 (DX4 100). That, and Winamp. Good times.

Memory has tencency to bend reality for better.

Every room with torches was max 9FPS on 320x200 on DX2 OCed to 3x50MHz, literally 50% performance over your PC. Turnig off all objects through console made torches vanished and FPS doubled.

My OCed DX4 got around 15fps, but I agree my memory of what was deemed “playable” back then probably wouldn’t stand today.

IIRC it came down to something crazy simple, like, using the FPU registers to bit-blit was the fastest way, but only on the genuine Intel Pentium.

Exactly. I remember schoolmates with AMD K6 (which had exceptionally weak FPU) having to purchase atleast the cheapest OpenGL GPU like Rendition Verite V1000 to play with decent FPS, while guys with 166MMX could play it software rendered.