Extreme Memory Conditions Testing : How to saturate RAM?

I would like to write a small piece of program that launches threads, consumes available RAM memory in a linear fashion, until a certain level, and stops (ideally, pauses until "enough" memory is freed and continues creating threads after that, and so on.)

I tried the following, but the list.Add(new byte[]) requires contiguous RAM space and drops an OutOfMemoryException, which is NOT what I am trying to simulate.

EDIT :
I have a multi-threaded memory-hungry application that eats up a whole bunch of RAM GB's. All I want is to isolate/reproduce that situation in "Lab conditions" to tackle it, i.e write an adaptive mem-monitoring / thread-limiter draft. I am using x64 OS an x64 Platform. To make it clear : The result I want to see is the Task Manager Memory Monitor going up straight due to the program.

    static void Main(string[] args)
    {            
        ComputerInfo ci = new ComputerInfo();
        D("TOTAL PHYSICAL MEMORY : " + Math.Round(ci.TotalPhysicalMemory / Math.Pow(10,9),3) +" GB");

        //########### Fill Memory ###############
        var list = new List<byte[]>();

        Thread FillMem= new Thread(delegate()
        {
            while (Process.GetCurrentProcess().PrivateMemorySize64 < MAX_MEM_LEVEL)
            {
                list.Add(new byte[1024 * 10000]); //<- I Need to change this
                Thread.Sleep(100); 
            }
        });

        FillMem.Start();

        //########### Show used Memory ###############
        Thread MonitorMem = new Thread(delegate()
        {
            while (true)
            {
                D("PROCESS MEMORY : " + Math.Round(Process.GetCurrentProcess().PrivateMemorySize64 / Math.Pow(10, 6), 3) + " MB");
                Thread.Sleep(1000);
            }
        });

        MonitorMem.Start();

        Console.Read();
    }