The 386SX ran at 16 MHz, was seven years old at the release of Windows 95 and was slightly below the stated minimum system requirements. By contrast, I had a 166 MHz Pentium (released four months after Windows 95) and I remember it being slow enough that I would go do something else while it booted.

I see references that mention that installing fonts can significantly impact boot time. Maybe the installed software and devices had a significant impact.