Duel processors wasn't supported at all by DOS or windows 95/98. You needed Windows NT which was still in it's infancy back then or some form of Unix. And while Unix on PC was very much a thing there were also lots of specialist unix workstations about. So duel CPU PCs were not common.
Multi processor setups only really got going when NT4 got properly established and WinTel started to make more in roads into the server space.
Yeah I was running windows NT, had a go at IBM OS/2 Warp and at the end was running Windows 2k Pro, as windows 95/98 etc only uses 1 cpu.


(I think the only video I saw of it maxed near time of launch was 3 or 4 GTX 280s in SLI)