With what exact MacBook Air and which Mac OS X version do you experience such behaviour in what applications?
How do you scroll (trackpad, mouse scroll wheel)?
With what exact MacBook Air and which Mac OS X version do you experience such behaviour in what applications?
How do you scroll (trackpad, mouse scroll wheel)?
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Have a look at Activity Monitor (Applications / Utilities /) and select All Processes and sort by CPU to see what the culprit may be.
Also check the "System Memory" tab to see what your "Page ins:", "Page outs:" and "Swap used:" are.