Modern computers do not have integrated sound synthesis hardware whatsoever, there has been no point in shipping that since the start of the 21st century. Unfortunately, that does mean that for playing legacy General MIDI content, users are stuck with poor quality software implementations like Microsoft GS Wavetable Synth and the (modern successor of the) QuickTime synthesizer, which were designed for slow computers with little memory in the late 1990's, and were trying not to compete with the high-end hardware of the time (because both license samples from Roland, who made such hardware).

General MIDI as a format basically died for serious computer use in the early 2000's. It's still a feature of some home keyboards and things, but it is a case where they genuinely do not “make them like they used to”. If you want the greatest possible GM support, you have to buy old hardware from e.g. the Roland Sound Canvas or Yamaha MU series, or obtain old software (no longer sold) like Roland Sound Canvas VA or Yamaha S-YXG50.

Thanks for the inspiration to dig this up for comparison:

https://youtu.be/fWnTYkCSZfA

Although I have to admit the cheesy versions do sound more familiar to me because I certainly had the most cheapo-grade sound hardware in any 90s PC I had access to.

I just now went searching to see if there were any better quality GM drivers for Windows that let you upload a soundfonts and it looks really dire out there! The one that mainly shows up is VirtualMIDISynth (https://coolsoft.altervista.org/en/virtualmidisynth). It seems like it supports Windows 11.

SoundFont® synths were never good. When Creative added this feature to their sound cards, they were trying to provide a cheaper alternative to dedicated hardware synths, but it did not match the quality (though it was still a step up from FM). And in the modern era, this obsolete format has somehow become more popular, now via software reimplementations, because of the catchy name or something?

I also want to point to Nuked SC-55, but that is also not based on SoundFont®.

If you have a high quality sample pack though it could sound good.

Most DOS emulators have great support for things like Roland's sound bank ROMs. It's pretty wild to suggest that on today's Windows sometimes the best way to experience MIDI files is to maybe download a questionably illegal ROM and load up a MIDI player written for DOS in DOSBox.

It seems like a missing market for vendors to directly support better sound fonts for Windows, maybe we'd see more files written for it again. But also, there's some sense that most of the best written General MIDI files for direct consumption were always the ones for videogames and it has been left as a matter for emulation for that reason as videogames themselves moved on to different tech.

Still though, there's something about loading Monkey Island 2 with a Roland MT-32 era sound font in DREAMM and experiencing what it does with "live" MIDI instrumentation that modern games wish they could do, and sounds nearly as good doing it. For certain values of nearly, of course. Redbook audio gave us all the lovely little "mistakes" of live band things like jazz performances that MIDI could never quite replicate in the same way. I wouldn't necessarily trade modern orchestration for MIDI in all cases, but it is easy for me to imagine that it might be great to see both side-by-side and the best of both in interactive media, best tool for each job style.