C / C++ / MFC

SYSTEM_INFO si;
GetSystemInfo(&si);
TRACE(_T("%u\n"), si.wProcessorArchitecture);

PS C:\Users\rjmac> Get-WmiObject Win32_Processor


Caption           : Intel64 Family 6 Model 142 Stepping 9
DeviceID          : CPU0
Manufacturer      : GenuineIntel
MaxClockSpeed     : 2701
Name              : Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz
SocketDesignation : U3E1

BOOL bIsIntel = FALSE;
SYSTEM_INFO si;
GetSystemInfo(&si);
bIsIntel = (si.wProcessorArchitecture == xxx);
if(bIsIntel)
{
    // execute some code (I cannot write here what kind of code)
}
else
{
    // execute else code
}

_Flaviu wrote:

I noticed that GetSystemInfo is taking a time

1. As someone already mentioned, the CPUID instruction gives you this information. It may be called using compiler intrinsics (#include <intrin.h>) on the Microsoft compiler. See here for fuller documentation. Pay attention to the EAX=0 function (Get Manufacturer ID).
2. It appears that the same information may be found in the Registry at HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\VendorIdentifier