Bike & Frame Weight

I have two bike, one that weight a little under 8kg, another that weight a little under 11kg.

The only difference I notice is the geometry, one is slacker, other is tighter, as well as the frame stiffness and how it handle road vibration.

Weight is something I only care about when carrying it up a flight of stair.

I'd notice that.

I'm 85Kg too, so the difference in total weight is small. But step out of the saddle, and you feel it. I doubt it translates to a meaningful amount of time/watts saved per 10 - 35 kph acceleration though. Its just a nice feeling.