My performance measurements of synchronous WCF calls from within a Silverlight application showed I can make 7 calls/s on a localhost connection, which is very slow. Can this be speeded up, or is this normal?

This is my test code:

const UInt32 nrCalls = 100;
ICalculator calculator = new CalculatorClient(); // took over from the MSDN calculator example
for (double i = 0; i < nrCalls; ++i)
{
    var call = calculator.BeginSubtract(i + 1, 1, null, null);
    call.AsyncWaitHandle.WaitOne();
    double result = calculator.EndSubtract(call);
}

Remarks:

• CPU load is almost 0%. Apparently, the WCF module is waiting for something.
• I tested this both on Firefox 3.6 and Internet Explorer 7.
• I'm using Silverlight v3.0