Internet painfully slow on my late 2012 iMac

Bruno09 said:

You might try disabling Sophos, then reboot and see how it works.


This can only slow down your computer.

On Mavericks and Yosemite, the OS maximizes the use of RAM to speed up the processes.

http://arstechnica.com/apple/2013/10/os-x-10-9/17/

Click to expand...

I'm just going by experience when I say it's made it snappier.
When I clean it up, I do so whilst keeping an eye on Activity Monitor and it shows the same result in that too when memory is freed up.