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    <p>Your benchmark is off, the margin should be way larger.</p> <p>For instance, on my computer, the C++ code takes 7.46s (compiled without optimisations, timed with the Unix <code>time</code> tool); the VBA code by contrast took 46s. This is a much more realistic margin (but I wouldn’t have been surprised by an even larger one – conventional, non-optimising interpreters are usually at least a factor ten slower).</p> <p>For one thing, VBA first has to read in the code and either interpret it line by line or transform it into an intermediate representation. Nevertheless, this intermediate code representation is still <em>interpreted</em>, not run directly by the CPU (or did you count the compilation time in C++?).<sup>1</sup></p> <p>In addition, VB(A) does a lot of redundant stuff in this code which is absent in C++: for instance, every single integer addition (which is implicit in your code in the incrementation of the <code>For</code> loop variable) is guarded against overflow. Essentially, this VB code</p> <pre><code>i = i + 1 </code></pre> <p>is transformed to the following pseudo intermediate code:</p> <pre><code>if i + 1 overflows then raise an overflow error end if i = i + 1 </code></pre> <p>… for <em>every</em> integer operation. That consumes quite a lot of runtime. The same goes for array (or here: cell) access operations.</p> <hr> <p><sup>1</sup> I <em>think</em> VBA uses an intermediate representation called <em>P-code</em> rather than line by line code interpretation.</p>
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    1. POWhat are the major reasons for run time differences between simple arithmetic operations - VBA vs. C++?
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    1. COI also felt like the margin should be higher. I'm curious to know what kinds of margins other people come up with.
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    2. CO@Stepan1010 See update in the second paragraph.
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    3. COCompiling it with a "release" build target instead of "debug" brought it down to around 15 seconds for me.
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