IIRC on a 486 DX/66 running Windows 95 you had to set Winamp to decode at half quality in order for playback to not skip (on a 128kbps file)

Yes, the fastest 486 systems could just barely do full-quality 44.1/16 MP3 decoding (DX4/100, etc) Even then a DOS player was a better bet than Winamp.

A SE/30 would be absolutely screwed.

As a comparison a basic home theatre pc these days with ryzen 1500x cpu, and GeForce 1030 fanless with GPU accelerated hevc in the video drivers, can decode up to about 350Mbps bitrate of HEVC 2160p 60fps using the latest VLC build. Beyond that it starts dropping frames.

edit: tests run using sample videos from here, if anyone wants to see what bitrate of 4K they can play back before it starts losing frames.

http://jell.yfish.us/

That sounds right - I think I could just push my 486 DX2/66 with Gravis Ultrasound to do 128kbps playback if I dropped into DOS and used Cubic Player.

On my Toshiba Libretto 30 I could get decent playback with the Fraunhofer decoder but not winamp, it was that marginal.

MpegDec is able to play MP3s on 68040 Macs (although with lowered quality settings and maybe even only mono). An SE/30 with an accelerator might be capable at really low quality.

http://www.jwgdesign.com/mpegdec/about.htm

My Amiga managed to do half-quality mono with a 40 MHz 030 under the bonnet (Hippoplayer IIRC). The 16 MHz 030 in the SE/30 would most likely not be able to do that in real-time, assuming that decoder isn't much more efficient compared to the MP3 datatype I used for the Amiga.

EDIT: Checked the web site. They're using the same encoder

I love thread like this where I can identify people's general age based on hardware they talk about. Ah daystar accelerator.

"Intel Inboard 386" and "Above Board Six Pack Plus"

I wonder how Opus compares, apples-to-apples on quality.