Sometimes, usually on the older systems, CPU is not enough to run heavy web applications. In such cases enabling GPU-Acceleration in your browser might help your system to run more smoothly.
To do so in Google Chrome please type "chrome://flags" into the URL-Address field. Then please find "Override software rendering list" section and choose "Enabled" from dropdown menu.
If you are using another browser please reffer to documentation of your browser to enable GPU-Acceleration.