Asp.net Website response time slow

I created many load test on my website and response times are starting to be slow after 100 customers.

To make things clear and simple, I created dummy asp.net default website and set on load method few methods that invoke WCF service:

protected void Page_Load(object sender, EventArgs e)
        {

                WcfClientService client = new WcfClientService ();
                 //syncrhron wcf service call 
                var testMethodOne = client.callMethodOne();
                var testMethodTwo = client.callMethodTwo();
                var testMethodThree = client.callMethodTree();




        }

I analyzed logs on a WCF service and WCF service is returning Request for every method in short time <200 MS. Asp.net -> WCF is SOAP. What can be a bottleneck sicne WCF is returning very fast response, but web is giving me a average response of 20 seconds (above 100 customers) for A Web form that has these tree service calls.

I'm invoking load test using jmeter

I can se on my iis many requests in a queue (for website)

Site and wcf service are hosten on a IIS 8.5 (Windows Server 2012R2)