When we tested AVG Ultimate, it did a really good job at stopping most threats from downloading and infecting our computer. It doesn't stop the download at the beginning of the process as other antivirus software does. Instead it waits until the download is nearly complete before snatching the threat and placing it in quarantine. There were a couple of threats that snuck through and infected our test computers. Most of these were found by AVG and removed during a deep virus scan. One threat was missed completely that we had to manually take care of. But overall AVG earned a decent score of 95 percent from us, which is slightly higher than scores given by other security testing labs.