How does software-based x86 emulation (ie OG Connectix Virtual PC) compare to current hardware-assisted virtualization? Were older methods more cycle accurate than what’s in use now?
You reminded me of my father showing up home one time (around 2005, I was 7-8) proudly showing a random CD. Then after few hours he called to show off a virtual Windows 98 PC running in a window on our Windows XP computer. I was fascinated, total awe for a few minutes. Virtual PC became the basis for my experimentation with Windows Server 2003 and newer + Windows clients (even multiple networked PCs ran nicely!), later Linux servers inside Virtualbox, and led to my career in software engineering.
Anyways to answer your question, Virtual PC and VirtualBox can fully run old as well as new software, and the performance hit is not that bad (I ran multiple virtualized Windows Servers when a PC had 1GB of RAM). However more modern virtualization methods can offer bare metal-like performance, which Virtual PC/Virtualbox will never be able to make.
Anyways to answer your question, Virtual PC and VirtualBox can fully run old as well as new software, and the performance hit is not that bad (I ran multiple virtualized Windows Servers when a PC had 1GB of RAM). However more modern virtualization methods can offer bare metal-like performance, which Virtual PC/Virtualbox will never be able to make.