Security tester AV-Test has revealed the results of its first Windows 8.1 tests, ranking 25 antivirus protection suites against each other to discover which offer the best protection, performance and usability.

At the top of the pile came BitDefender and Kaspersky, scoring perfectly in all three categories. Both security suites, which require payment, received 18 out of 18. Avira Internet Security 2014 and F-Secure Internet Security were in hot pursuit, scoring 17.5 and 16 respectively.

Using Microsoft Windows Defender 4.3 as a baseline for comparison, AV Test enabled all default security features unless the security software itself turned them off. With no third-party antivirus protection running, Windows 8.1 Defender scored 11 out of 18.

Anything better than nothing

The three largest free security suites, Panda Cloud Antivirus Free edition, AVG Free AntiVirus 2014 and Avast AntiVirus 2014 scored lower than paid software, as might be expected. That said, AVG Free tied with its paid relative AVG Internet Security, both earning 15 out of 18.

Perhaps most interestingly (or worryingly if you happen to use them), Kingsoft Antivirus and AhnLab Internet Security both scored lower than Windows 8.1 without any extra software installed, with 10.5 out of the 18 for the former and a rock-bottom 9.5 out of 18 for the latter.

Kingsoft lost all of its points on performance, scoring 0, while AhnLab's software dropped points across the board. The results seem clear: if you want the best all-round protection on the latest version of Windows, your best bet is to pay for it.

It's also good new for people with light wallets to see that the free options from the big security companies can still mix it with the top paid software, proving you don't have to bust the bank to forfeit antivirus protection on your PC.