IMAC Intel constantly freezes

I am so tired of this expensive fancy APPLE IMAC freezing up. My Windows laptop doesn't do it. It constantly freezes up with I try to send an email from Firefox and when I go from one webpage to another. The hard drive is good and there is no memory problem. I see this is a common problem and for Apple to have not come up with a fix is ridiculous. I have all the most recent updates to the OS (10.9) and it has been doing this with earlier versions. Has anyone figured this out.