Difference between 'As compared to' and 'When compared to'

Please see this :

Both forms occur in objective writing, but "when compared to" occurs more often in personal and persuasive writing.

"As compared to" is the standard form in the reporting of statistics from research. It's used in scientific, technical, and business writing. It's very impersonal.

"When compared to" is a short form of "when one compares (X) to (Y)," and is used when the act of comparison itself is relevant. This form also occurs in persuasive writing, when the writer seems to be asking the reader to do the comparing. Given the context, Sentence 1 is more appropriate.