There are bottlenecks other than the "speed" of the disk.  Your processor speed, your harddrive read capabilities, and your card reader write speed/if you are using firewire, USB or USB2... so even tho i could say your manual counting was flawed in the experiment, you need to also take into account the overall speed of each test could have been slowed considerably by these other factors.

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography