Open your registry and find the key below.
Create the following values, as most of these values will not already exist you will need to create them by clicking on Edit -> New -> DWORD or String Value and then set the value as shown below.
DefaultTTL = "128" (String Value)
Specifies the default time to live (TTL) for TCP/IP packets. The default is 32.
DefaultRcvWindow = "32767" (String Value)
Specifies the default receive window advertised by the TCP/IP stack. The default is 8192. If you're using Windows 98, Me or 2000 and have a latent network, you can try increasing the value to 93440, 186880, or 372300.
PMTUBlackHoleDetect = "0" (String Value)
Specifies whether the stack will attempt to detect Maximum Transmission Unit (MTU) routers that do not send back ICMP fragmentation-needed messages. The default is 0.
PMTUDiscovery = "1" (String Value)
Specifies whether the TCP/IP stack will attempt to perform path MTU discovery as specified in RFC 1191. The default is 1.
SackOpts = "1" (String Value)
Enables support for selective acknowledgements as documented by Request for Comment (RFC) 2018. Default is 0.
Tcp1323Opts = "1" (String Value)
Controls RFC 1323 time stamps and window scaling options. Possible values are: "0" = disable RFC 1323 options, "1" = window scale enabled only, "2" = time stamps enabled only and "3" = both options enabled.
To increase performance even further follow the instructions here and increase the MaxMTU to 1500 (or 1492 if your provider uses PPPoE).
Exit your registry and restart Windows for the change to take effect.