Using our own collection of malware, Avast detected twice as many dirty files as Windows Defender, though that might have to do with the way each program counts individual files within an infected archive. Windows Defender needed to pull out a win in this round to keep the race interesting, but it doesn’t have the legs to compete with Avast. Subjectively, surfing the web and opening up programs felt equally snappy regardless of which AV program was running. If this were a presidential race, it’d be too close to call.
On the flip side, we recorded 4,035 in PCMark 7 with Avast installed versus 4,011 with Windows Defender. Boot times were virtually unaffected, with Avast introducing a startup penalty of just a few seconds. We slapped a 120GB Kingston SSDNow V300 drive onto an Asus P6X58D Premium motherboard with an Intel Core i7-930 processor, 4GB of DDR3/1333 RAM, and a Radeon HD 5850 graphics card. If you’re rocking a solid-state drive with Windows 8 on a relatively modern machine, you’re unlikely to notice a performance impact with either Windows Defender or Avast installed.
