Through use of the selective startup features of MSCONFIG, I determined that this pause is due to the loading of the SysTray executable. I really should just look away for those seconds - stare at my shoes, the wall, the ceiling - but no, principle dictates that this must be resolved somehow. One irritating 'feature' of the upgrade is that, after the system boots into windows, I get a 'working-in-background' mouse cursor for 3-5 seconds, after everything else has finished loading.
I recently built a Windows 95 'gaming' system, and then ended-up having to upgrade to Windows 98SE to gain use of a USB-connected peripheral.