Then i suggest do the next step of troubleshooting for performance, which involves checking that your drivers are updated, windows is updated, and if that doesnt help try deffragging the computer, and running some scans for nasty trojans with some free apps like spybot S&D and Malwarebytes.
If after all that, well it could be stuff you have installed is interfering (more than one Antivirus app being used? over protective 2nd firewall programs? too many system bar apps running with not enough resources spare).