Hi. Very thorough problem statement. I wish all looked like yours. I'm a retired comp. sci. prof as well as a pro player.

Couple of reactions to start: My first deal with your questions. But if you want a BIAB tip, skip to the bottom.

In your first group, I would expect the problem would worsen with option #3, resource intensive VSTs. Also somewhat from your first option, after repeats, if you have limited RAM. I would have thought 8 GB was enough, though, unless the VSTs are sucking it up and you have other things running (one of your tests is to restart with only BIAB running; good idea).

MIDI normally presents almost no load to a system, especially the CPU, unless it's a huge VST playing it. And I've never heard of MIDI input causing problems except for a MIDI wind controller or some such that can overwhelm the input; if you have one of those, tell us because you can filter it.

About your computer, try running the free utility, Geekbench 5 and report your single-core score. I'm a bit puzzled by your CPU being only 2 GHz but it's a quad core. So I'm guessing this is around six years old? And run the free DPC Latency Checker, which will read 1000 ms too high but still works in Windows 10. Instructions on the site. This will make sure there are no other errant drivers.

About drivers, ASIO4ALL is not an ASIO driver. It is an MME driver made to substitute for ASIO, but it does not bypass the CPU as ASIO does so there is little point. If your sound card has an ASIO driver, absolutely try that, then adjust your ASIO buffers a bit slower by degree. Which 'generic' sound card is it? That might prove to be the better solution here, but let's hear what you have.

I like the idea of installing the program on the internal SSD (that's what I do) and running the RealTracks and RealDrums (that take up most of the space) from the external drive. You said your external drive is an SSD too - great - so you must have transferred everything from the PG Music-supplied drive?

BIAB things to try:

Does your song tempo match fairly closely to the style tempo and/or RealTracks recommended tempo range?

You've concentrated on MIDI questions, but does an offending song have RealTracks on it as well? If so, if you remove them, does it fix the problem? There are adjustments we can recommend if so. And you could also try Song Settings by Ctrl+N and check the box for This Song Has Playback Problems.

When all else fails, do Options, Return to Factory Settings, Most.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Presonus 192 & Faderport 8, Royer 121, Slate VSX, Adam Sub8 & Neumann 120 monitors.