Windows will limit connections to a single HTTP 1.0 server to four simultaneous connections.
Connections to a single HTTP 1.1 server will be limited to two simultaneous connections. The
HTTP 1.1 specification (RFC206

mandates the two connection limit while the four connection
limit for HTTP 1.0 is a self-imposed restriction which coincides with the standard used by a
number of popular Web browsers.
Open your registry and find the key below.
Create two new values, or modify the existing values, called 'MaxConnectionsPerServer' and
'MaxConnectionsPer1_0Server'. Change the values to equal the number of simultaneous
requests allowed to a single HTTP server, the default values are 2 and 4 respectively.
Restart Windows for the change to take effect.
Note: By changing these settings you are causing Windows to break the HTTP protocol
specification for any Internet applications running on your machine.
Note: This affects all Windows Internet applications that use the standard API, including
Internet Explorer.
Registry Settings
User Key:
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
Value Name:
MaxConnectionsPerServer
MaxConnectionsPer1_0Server
Data Type:
REG_DWORD (DWORD Value)
Value Data:
Number of Simultaneous Connections