As has been said in many different ways, above, the difference between two properly adjusted, lubricated and functioning bearings should be nearly nil. And if a bearing was poorly lubed or maladjusted enough to notice, you'd .... well, you'd notice. Grinding in the bearings, or tough to turn the axle at all. And if the bearing was adjusted to be a bit too tight (to much "preload", in the parlance), and this created friction, it would heat up the axle, lengthening it a bit, to reduce the preload. If the axle does not offer much friction when turned with your fingertips, it's probably not too bad. Seal friction can offer a bit of resistance, and is more pronounced in new bearings.

I guess your question is one of degree. If you spin one wheel and it spins for two minutes, and you spin the other wheel and it goes for one minute, but both wheels appear to have smooth function, read what FBinNY says above: stop obsessing and ride... If the second wheel stops after spinning an eighth of a turn, with a grinding sound... Well, yeah, that will affect your speed.