if you look at the benchmark details you will see that the 40% overclock actually netted a 40% boost in the CPU benchmark score
PS while overclocking helps, a device with more RAM helps even more especially when paired with a custom ROM. if your device has 1GB of RAM, then you can have custom roms where more elements of the OS are buffered into RAM, this allows for a more iphone like experience when it comes to transitions in the UI. By default, android unloads UI elements and other graphical elements from memory when they are not visible, but it can be modded to keep it so you get a smoother UI experience, eg widgets not having to redraw when you rotate the screen, and all native UI's within the OS load instantly. (takes more RAM but not an issue if you have 1GB
PS for really good demo of what overclocking can do, try playing HD video that is not GPU accelerated, on my HP touchpad, I can have 3 720p flash videos playing at the same time with no lag when at 1.89GHz
I can also play a single, large 1080p 10 bit movie (10+GB in size) smoothly and that MKV file is not supported by the GPU so that is all CPU
If you have an android or any other device that can be overclocked, then you owe it to yourself to overclock it, the benefits are not noticeable at all times but during the times when they are noticeable, they are really really noticeable.