So, what's the minimum to play the following?
- 44100 Hz
- 16-bit
- stereo
- uncompressed, or with loseless compression - so no hardware MP3 decoders
- WAV, or similar format - no real-time generation/mixing
- length only limited by the storage - no preloading into RAM

Basically, the storage needs to sustain 176 KB/s reads.

Let's consider two categories:
- local storage
- network-attached storage

My attempts so far...

Hardware:
- CPU: 286 @ 12 MHz
- HDD: ST3660A - IDE, 540 MB, 528 MB usable
- LAN: NE2000plus3
- sound: Sound Blaster 16 CT1740

Software known to play CD-quality WAV files on 286:
- Creative Disk Wave Playback 1.10 (WPLAY)
- QuickView 1.03a, but not 1.03b
- Windows 3.1 Media Player, 286-compatible drivers exist for SB16 and PAS16

Tested network client software:
- Microsoft Network Client version 3.0 for MS-DOS, using TCP/IP
- mTCP NetDrive (Jan 10 2025), MTU 1500
- mTCP NetDrive (Apr 28 2025), MTU 1500, 4 KB cache

First, benchmarking the storage, by measuring the execution time of "copy /b testfile nul":
- HDD: 813 KB/s (711 KB/s in CheckIt 3.0)
- MSNC: 199 KB/s
- NetDrive (Jan 10 2025): 303 KB/s
- NetDrive (Apr 28 2025): 469 KB/s

Playback, using WPLAY:
- HDD: OK
- MSNC: bad
- NetDrive (Jan 10 2025): OK
- NetDrive (Apr 28 2025): OK

Now, switching it to de-turbo...
- CPU: 286 @ 6 MHz
this machine is still faster than the 6 MHz IBM 5170, due to the unnecessary wait states in the IBM

Benchmarks:
- HDD: 591 KB/s (645 KB/s in CheckIt 3.0)
- MSNC: 116 KB/s
- NetDrive (Jan 10 2025): 227 KB/s
- NetDrive (Apr 28 2025): 307 KB/s

Playback, using WPLAY:
- HDD: OK
- MSNC: very bad, of course
- NetDrive (Jan 10 2025): bad
- NetDrive (Apr 28 2025): OK

Conclusion:
286 @ 6 MHz - and no wait states - is good enough, with both local and well-optimized network storage.

Now, challenging anybody with the 6 MHz IBM 5170, or anything XT-class!