Is C++ faster than Visual c++ (.Net)

If C++ your code is using .NET framework/compiler/CLI than it would be slower than native C++.
For example, and int is actually Int32, which is derived from System.Object and has some attributes inherited. It would have runtime penalty (exceptions etc).
Whereas a native int would just be 32-bit number, and nothing else attached to it.

An assignment which is higher than int's range would cause an exception for Int32, but would just overflow/underflow for native int.

When it comes to speed its the processor which processes the native code so the native code produced with C++ native dll and C++.net dll should be identical.

The .net framework keeps JIT to prepare native code from IL code and JIT is asked to prepare only if some method is being invoked very first time during the execution process. It may take some time over executing native code directly. but the alternate is creating a native image with ngen.

so once the code is ready in Navite image there will be hardly any performance hit as OriginalGriff also said.

If calling a native dll in .net code causes Marshalling then it's an overhead too.

To speed-up the process you can take benefit of multi-core processors.

Thanks,
Hemant

In general, VC++ .NET is a confusing name. In fact they don't call it that any more for this reason. It's just VC++ 2010 now. Writing pure native C++ would be your fastest option. That said, the performance difference between native and managed code is often irrelevant because JITed code runs natively. So it's not just a black and white situation here, and there are many factors that affect speed. An efficiently written mixed mode app that uses C++/CLI to mix managed and native code may actually be faster than a less efficiently written pure native C++ library (that does the equivalent). So these are factors you need to consider and eventually you may need to do some trial and error to hit upon just that right combination of managed and native code.

Probably, the fastest way to do it is to do your time critical stuff in a C++ native DLL (rather than a C++.NET DLL) and call that from your VB.NET or C++.NET software. Switching to C++.NET will probably have little or no effect on the execution speed.

Try it and see: Use the Stopwatch class and get some numbers!

Its clear that C++ is fastest then V-C++. Of-course if something is managed by CLR/.Net Framework then, it must be costing something. What it costs it speed... but what is the gain... gain is code reusability... portability... better error handling... all that worths a lot.