Pop Quiz - Debug Event Loop and Timeslice Quota

You might have heard of the Popek and Goldberg Virtualization Requirements. In theory, debugger shares a similar set of problems as virtualization, this is especially true for func-eval (Function Evaluation). Here goes a pop quiz about the side effects of the presence of debugger:

 #define WIN32_LEAN_AND_MEAN

#include <Windows.h>

#define LOOPCOUNT 10

ULONG g_ulVariableA;
ULONG g_ulVariableB;

DWORD WINAPI ThreadProcA(LPVOID lpParameter)
{
  while(true)
  {
    for(int i = LOOPCOUNT; i; i--)
      ++g_ulVariableA;
  } // add a breakpoint here (BP1)
  return 0;
}

DWORD WINAPI ThreadProcB(LPVOID lpParameter)
{
  while(true)
  {
    for(int i = LOOPCOUNT; i; i--)
      ++g_ulVariableB;
  } // add a breakpoint here (BP2)
  return 0;
}

int ExeEntry(void)
{
  SetProcessAffinityMask(GetCurrentProcess(), 1);
  CloseHandle(CreateThread(NULL, 4096, ThreadProcA, NULL, 0, NULL));
  CloseHandle(CreateThread(NULL, 4096, ThreadProcB, NULL, 0, NULL));
  return ERROR_SUCCESS;
}

Let's say we have two breakpoints BP1 and BP2 as illustrated:

1. Each time I launched the application from the Visual Studio Debugger on my desktop machine (Xeon Quad core, Windows 7 64bit), BP2 would always get hit before BP1. On my laptop (Dual core, Windows 7 32bit), BP1 will get hit before BP2.
2. If I made BP2 as a conditional breakpoint with a false condition (e.g. 0 == 1) on my desktop machine, I will have to wait a few seconds before BP1 got hit.
3. If I made BP1 as a conditional breakpoint with a false condition (e.g. 0 == 1) on my laptop, I never got a chance to hit BP2, and my CPU usage would always stay at around 50%.

Do you share a similar experience as I have? I have already put some hints on the title of this pop quiz, happy debugging :)