c++ - Launching the program from Visual Studio debugger is faster than launching it from outside -

summary:

i saw when ran program visual studio (f5), pair of multiplications took around:

x64: 3.8~ ms

win32: 4.5~ ms

however when ran outside took:

x64: 6.59~ ms

win32: 6.62~ ms

does have idea why happening?

more info:

i wanted test matrix multiplication speed of glm library , iterating on number of them hash map, vector , array. (to calculate transformation matrices rendering)

so, using queryperformancecounter, tested 50000~ multiplication pairs 1000 times average timing. (default visual studio 2013 empty project release configuration)

normally 1 expect program faster when ran outside of visual studio, tried again setting program priority programmatically, made no difference.

to give idea example loop looks this:

    timer.start();     (int j = 0; j < 1000; j++)     {         (int = 0; < objectsvector.size(); i++)         {             if (objectsvector[i]->mmeshrefid > 0)             {                 results[i].worldtransformationmatrix = objectsvector[i]->getworld();                 results[i].mmeshrefid = objectsvector[i]->mmeshrefid;             }         }     }     timer.gettimediff(); 

if wanted take @ or try full code link here: https://www.dropbox.com/s/xilydyvp3lublrk/matmult.zip

p.s: found link, think irrelevant because have no dlls: program runs slower when launched outside of visual studio

p.p.s: 2 windows 8 pcs gave same results, while timings same under windows 7 pc (ran little slower (0.8~ms) visual studio, should case)

more: replaced glm own code represents matrices float array, while timings better, running visual studio still faster. still don't know how achieve speed outside visual studio.