 <p>Think outside the box. Which application of the ones you use regularly does this? A debugger of course! But, how can you achieve such a behavior, to emulate a low cpu?</p> <p>The secret to your question is <code>asm _int 3</code>. This is the assembly "pause me" command that is send from the attached debugger to the application you are debugging.</p> <p>More about int 3 to this <a href="http://stackoverflow.com/questions/3747852/int-3-0xcc-x86-asm">question</a>.</p> <p>You can use the code from <a href="http://www.codeproject.com/KB/threads/pausep.aspx" rel="nofollow">this</a> tool to pause/resume your process continuously. You can add an interval and make that tool pause your application for that amount of time.</p> <p>The emulated-cpu-speed would be: (YourCPU/Interval) -0.00001% because of the signaling and other processes running on your machine, but it should do the trick.</p> <p>About the low memory emulation: You can create a wrapper class that allocates memory for the application and replace each allocation with call to this class. You would be able to set exactly the amount of memory your application can use before it fails to allocate more memory.</p> <p>Something such as: <code>MyClass* foo = AllocWrapper(new MyClass(arguments or whatever));</code> Then you can have the AllocWrapper allocating/deallocating memory for you.</p>