I had lots of audio pops and sound loops that would briefly freeze the game.
I did the following and got much more smooth performance:
In Steam, right-click, Properties on the Black Mesa icon. Set Launch Options…
That’s to allocate 1 GB of RAM to the heap.
I also made the following changes to my autoexec.cfg file in C:\Program Files (x86)\Steam\steamapps\sourcemods\BMS\cfg. You can test these without editing the file in the developer console.
The first two made a huge difference for me. The last one (coupled with the heapsize change) improved load times somewhat. snd_async_showmem will also show which .wavs are preloading.
Intel Core2Duo E6550
AMD Radeon HD5770
edit: I had this in there but not sure it’s doing anything meaningful. Cache seems the same size regardless.