http send get request with parameter

Question

calling url using httpclient as httpwebrequest works slowly after 1 lac request,please help me and i need to send 6-7 lkh get request to end user.currently i am using below
method

WebRequest request = WebRequest.Create(URL);

WebResponse response = request.GetResponse();

new StreamReader(response.GetResponseStream()).ReadToEnd();

response.Close();