The latency you describe is typically due to the system being overworked. Do you have antivirus software running? This is very often the cause.

Go to the APPLICATIONS/UTILITIES folder and click on the ACTIVITY MONITOR to see what processes are running. The monitor will show you what resources are being used in real time. You can shut down processes you don't want or need.

If you have antivirus software running, you may want to reconsider. Mac's have excellent built-in virus protection, if you enable the firewall and configure the security settings on your browser. Firefox is generally better than Safari, IMHO.

Hope this helps. If not, a trip to the Apple store may be in your future ;-) They can fix it on the spot.