title: How to be sure if a processor is 32bits or 64bits ? Are dual core processors 32 or 64 bits?
body: <p>Having a Macbook Pro with windows installed thanks to bootcamp, I have several questions:</p>
  
  <ul>
  <li><p>Under windows, I see that processes only use 50% maximum of the CPU charge, is that because the processor is a dual core and because the process is not multi-threaded ? Should I install windows xp version 64 bits instead, to have better performance ?</p></li>
  <li><p>Are all dual core processors 64 bits ? How can I check it with C or C++ to be sure that the native is 64 bits and not 32 bits ? I tried to print:</p>
  
  <p>sizeof(void*);</p></li>
  </ul>
  
  <p>it says 8, so it would mean 64 bits, but I'm not sure...</p>
  
  <ul>
  <li><p>Does dual core explicitey means that if it has 2 32 bits cores, the processor itself supports 64bits instructions ? Is this the x86_64 architecture ?</p></li>
  <li><p>Is is delicate to emulate PS2 games because the original game has 128 bits instructions ?</p></li>
  <li><p>Why are long double 128 bits while</p>
  
  <p>sizeof(long long);
  sizeof(long);</p></li>
  </ul>
  
  <p>both output the same thing ?</p>