扫描进程虚拟内存数据区域的问题

SYSTEM_INFO SystemInfo;
ZeroMemory((void *)&SystemInfo,sizeof(SystemInfo));
GetSystemInfo( &SystemInfo);
DWORD high = (DWORD)SystemInfo.lpMaximumApplicationAddress;
DWORD low = (DWORD)SystemInfo.lpMinimumApplicationAddress;

HANDLE handPross;
handPross=OpenProcess(PROCESS_ALL_ACCESS, FALSE, m_dwProssId);

MEMORY_BASIC_INFORMATION mi;

VirtualQueryEx(handPross, (void *)low, &mi,sizeof(mi));
int nSizePage=0;
for(low;low<high;)
{
int dwAddress;

if(mi.State == MEM_COMMIT&&mi.AllocationProtect==PAGE_READWRITE)//设置搜索条件
for(dwAddress=0;dwAddress<(int)mi.RegionSize;dwAddress+=4)
{

  DWORD lpleng;
  DWORD dw;
  ReadProcessMemory(handPross,(void *)low,(LPVOID)&dw,4,&lpleng);
if(dw==val_word)//val_word为我要搜索的值
{
CString st1;
  st1.Format("地址 %0X 值%d",low,dw);
  MessageBox(st1);

}
low+=4;
}
ZeroMemory((void *)&mi,sizeof(mi));
VirtualQueryEx(handPross, (void *)low, &mi,sizeof(mi));
}
我用mi.State == MEM_COMMIT&&mi.AllocationProtect==PAGE_READWRITE这样的条件定义的时候扫描一个最简单的进程也有十来M，扫描QQ有75M左右，这样扫描空间是不是太大了？还有没有能扫描只有数据区域的方法？还有当我扫描一个程序的时候N久都没扫描完，而我用金山游侠的时候几乎1秒就搞定了，还进行了三种方式的扫描(BYTE,short,UINT)，为什么金山游侠能那么快？请高手指点~谢谢~~~