The best way is using OpenDNS servers or Google DNS servers. You can use OpenDNS or Google DNS servers. This is by far the best way to increase internet speed. I will post step by step process. Just follow those steps.
1. Click Start button and goto Control Panel
2. Click Network Status or Network and Sharing Center
3. Then choose your Network Connection
4. Then click Properties
5. Click “Networking” tab and Check Internet Protocol Version (TCP/IPv4) and click Properties
6. Then Choose “Use the following DNS server addresses”
7. Then enter “Preferred DNS server” as 188.8.131.52 and enter “Alternate DNS server” as 184.108.40.206 and Click OK.
8. Now you need to configure flushDNS. Inorder to do that Goto Run and type Command and press Enter. Now type ipconfig/flushdns in the black box that is appearing on the screen and press Enter. Thats it now you have successfully configured flushdns.
Below is the screenshots in Windows 7.
You can use Google DNS also to increase the speed. The process is same as I mentioned above. You just need to change Prefered DNS server as 220.127.116.11 and Alternate DNS server as 18.104.22.168 and don’t forget to flushdns as I said you in Step 8.