I am running a 64bit system right now, that has had CIS on it, not once did i get an infection, or not feel protected. As a matter of fact, not only did it not get an infection, but compared to other Suites I have tried, CIS was extremely light, stable, and fast on my 64bit system! I had no errors, was a smooth install, everything worked like clock-work. I should mention also, that my laptop, well, it is a single core processor, that just doesnt have a whole lot of get up n go.. Running CIS on it, made it very responsive compared to some of the other Suites I have tested.