# Re: Article: Increasing the D Compiler Speed by Over 75%

```On Monday, 29 July 2013 at 10:15:31 UTC, JS wrote:
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Actually, it is a 43% speed improvement. 0.43*21.56 = 9.27s

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So if it is 43% faster, it means it's reduced the time by 9.27s or, 21.56 - 9.27 = 12.28 seconds total.
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Now, if we started at 12.28 seconds and it jumped to 21.56 then it would be 21.56/12.19 = 1.77 ==> 77% longer.
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No... it's not. How hard is it to understand that "time" != "speed"? Quote:
```"Increasing the D Compiler ***Speed*** by Over 75%"

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If you increase your speed by 100%, then you decrease your time by 50%. If you increase your speed by 75%, then you reduce your time by 43%. It's *not* that complicated.
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Feel free to reason in whatever unit and or dimension you want, but Walter's affirmations are neither wrong nor misleading.
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BTW: According to your "logic", a car that runs 200 mph is a "50% speed improvement" over a car that goes 100 mph. Makes perfect sense.