c++ recv function is slow - c++

Question

I have a program, that needs to communicate with a server through a HTTP POST request and then receive the answer from the server. The send and receive code is in a loop and should be executed as fast as possible. My problem is, that the recv()-function needs about 500ms until it finishes. The length of the answer i receive is unknown.
if (send(m_socket, buffer, strlen(buffer), 0) != strlen(buffer))
{
cout << "HTTP: Error sending:" << WSAGetLastError() << endl;
return "0";
}
const int buflen = 322;
char buffer2[buflen];
recv(m_socket, buffer2, buflen, 0);
What can i change to decrease the time of the recv()-function to a few ms?
Here's the complete code:
WSADATA wsaData;
SOCKET m_socket;
int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult)
cout << "Error" << endl;
m_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (m_socket == INVALID_SOCKET)
cout << "Invalid Socket : " << WSAGetLastError() <<endl;
setsockopt(m_socket, IPPROTO_TCP, TCP_NODELAY, "1", 1);
sockaddr_in clientService;
clientService.sin_family = AF_INET;
inet_pton(AF_INET, "127.0.0.1", &clientService.sin_addr.s_addr);
clientService.sin_port = htons(80);
if (connect(m_socket, (SOCKADDR*)&clientService, sizeof(clientService)) == SOCKET_ERROR)
{
cout << "Connection Failure"<<WSAGetLastError()<<endl;
WSACleanup();
return 0;
}
while(alpha)
{
if (send(m_socket, buffer, strlen(buffer), 0) != strlen(buffer))
{
cout << "HTTP: Error sending:" << WSAGetLastError() << endl;
return "0";
}
const int lang = 322;
char buffer2[lang];
recv(m_socket, buffer2, lang, 0);
cout<<buffer2<<endl;
}