I would say the 17% CPU load is strangely low...
K5 PR90 is at par with Pentium 90 in fixed-point code, but in floating-point is worse, and MP3 decoding uses floating-point heavily...
so, it's normal for that poor excuse for a CPU to be on the border, isn't it?

Grzyb wrote on 2023-02-13, 11:04:

I would say the 17% CPU load is strangely low...
K5 PR90 is at par with Pentium 90 in fixed-point code, but in floating-point is worse, and MP3 decoding uses floating-point heavily...
so, it's normal for that poor excuse for a CPU to be on the border, isn't it?

Well, yeah - K5 family wasn't any kind of success. But in this particular case those measurements of CPU load reflect reality of usage.
With the ISA sound card mp3 playing is disrupted, UI of the OS is extremely slow to respond - exactly like any machine under huge load. When with CT4810 PCI card mp3 play is fluent and same with OS UI, machine responds quickly.

It sounds like some sort of driver deficiency but maybe the DMAs of ISA lock up the main bus and that is where the problem comes. I suppose you don't have other ISA cards to try ?

Did you try another player than Winamp?
I remember back in the time that i expercienced same thing with my Windows 95 K6-2 rig of 1999 with the Winamp of the time and an ISA SB16. That's why i moved to PCI sound card and it solved my problem.

Grzyb wrote on 2023-02-13, 11:04:

MP3 decoding uses floating-point heavily...

Some versions of WinAmp uses an integer-based MP3 decoder.

Tiido wrote on 2023-02-13, 11:34:

It sounds like some sort of driver deficiency but maybe the DMAs of ISA lock up the main bus and that is where the problem comes. I suppose you don't have other ISA cards to try ?

I was thinking that it was driver related as I never had issues with WinAmp using ISA sound cards, at least with version 2.x. There were multiple drivers for ESS AudioDrive sound cards, which can be either WDM or VxD in Windows 98.

Assuming 16-bit, 44.1 KHz, stereo audio, that's just 176,400 bytes/second of decompressed audio data on the bus, well below what ISA can handle. With a 430FX chipset, I'm guessing you're using a PCI graphics card and the on-board IDE controller, which is also PCI, so you shouldn't have much contention for the ISA bus.

Instead, I wonder if this has something to do with DirectSound acceleration or sound mixing. The driver that ships with the OS for the ES1869F might not support DirectSound. DirectSound is supposed to have lower CPU utilization than WaveOut. See what WinAmp is using on these cards.

Also, I don't think the ES1869F supports hardware mixing of multiple PCM audio streams, while the AudioPCI does. Software mixing is taxing on slower CPUs.

I did additional tests. Switched to i430VX system with AMD K5 PR100. Then changed sound card to Aztech MM Pro 16III. No success. Next used drivers from vogonsdrivers.com for the Aztech card and CPU utilization dropped from 100% to about 50% for 192kbps/48kHz and to about 38% for 22kHz.
FInally I switched sound card to Ensoniq AudioPCI again and got about 50% for 192kbps/48kHz and to about 32% for 22kHz.
For all above looks like (I suppose) VxD drivers acts like PCI sound card but I do not understand why I got so low measurements before for PCI card?

Again it is CPU bound due to windows 98SE, this is not smart to do with anything less than 200MHz. Try Pentium 200 or so.

Cheers,