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.

Winner: Avast Round 4: Performance Impact Plus, you can easily schedule scans in Avast to run during times when you’re not sitting at your PC, such as after-work hours (assuming you leave your PC on 24/7). Avast clocked five minutes and nine seconds to scan the same data, and though it also didn’t get any quicker during subsequent scans, it’s still significantly faster than Windows Defender. That’s an indication that Windows Defender doesn’t skip over files that haven’t changed since the last time they were processed. Running a full system scan with 30GB of data on a solid-state drive took 20 minutes with Windows Defender, and subsequent scans took just as long. Windows Defender uses the same pokey scan engine as Microsoft Security Essentials, and since there’s no easy way to schedule scans, it’s even more problematic. Avast is chock-full of settings and provides excellent real-time protection, no matter where the threats come from.

Windows defender and avast