It's really hard to evaluate the performance of different bikes because there are so many variables. Tire rolling resistance, bearing drag, freehub drag, and wind resistance will all affect how well it holds the speed. So will the road surface, slope, and wind.
I have found that older aluminum bikes feel faster than my new carbon bike because you can feel more of the road vibrations through the stiff frame and narrow, high pressure tires. This is purely an illusion though!