Independent testing lab AV-TEST has revealed its list of the best security solutions for Windows 8.1, according to the company’s November/ December 2013 tests.

Six suites were locked at top of the list for protection with maximum 100% scores in both months: F-Secure Internet Security 2014, Norton Internet Security 2014, Bitdefender Internet Security 2014, Avira Internet Security 2014 and – after topping the AV-Comparatives table last month – Kaspersky Internet Security 2014.

While they each dropped a couple of percentages points in one of the months, AV-Test’s scoring system means three further packages were also given full marks. Panda Cloud Antivirus 2.3 (the best of the free tools), eScan Internet Security Suite 14.0 and Norton Internet Security Suite 2014.

Bitdefender and Kaspersky topped the performance table, meaning their products had the least effect on system speed. Meanwhile, Norton Internet Security lagged far behind, a disappointing 19th out of 24.

AV-Test also tries to assess usability by counting the number of false positives a tool raises, placing ESET Smart Security 7.0 and Kingsoft Antivirus 2013 at the top of the list. The free tools score well here – Avast Free AntiVirus 2014 is 4th, Panda Cloud Antivirus 6th – while Comodo Internet Security Premium 6.3 is bottom of the pile. Keep in mind that this figure really needs to be considered with the other scores, though: a higher number of false positives might be more acceptable if the package also traps all real malware.

If you’d like to know more, summary test results are available at AV-TEST’s site.