I have one SSD that is my boot drive. It has Windows of course and most applications (and many of those give no choice but to install to the boot drive). It has no data, with the exception of BIAB where both the program and my songs are on the SSD. I keep good backups of songs of course, since my SSD is one of the earliest models.

I would think your setup, with BIAB on the SSD that is NOT a boot drive, would be as fast as it gets for BIAB, with no calls to that drive for Windows. I thought about doing it that way but chose to have the benefit of the fastest loading of Windows on my five-year old PC.

In your case, a faster CPU would be the next logical upgrade for BIAB regeneration speed.

I'm assuming you are running Windows 64-bit and have 4GB or more RAM.

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; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.