Microsoft has recently released an important update for its Windows Defender antimalware program. This update will significantly improve the performance of Firefox, enabling its users to browse the web more smoothly.
Firefox users have been experiencing performance issues while browsing the web for over five years due to the high CPU usage of the Antimalware Service Executable component of Windows Defender (MsMpEng.exe). Mozilla developers have finally discovered the source of the problem, which was the VirtualProtect function, and worked with Microsoft to resolve it.
Microsoft’s recent update for Defender’s antimalware engine, version 1.1.20200.2, solves the issue by consuming less CPU than before when monitoring the dynamic behavior of any program through ETW.
The impact of the fix is huge for Firefox users, and it will consume approximately 75% less CPU when monitoring Firefox. Firefox relies heavily on VirtualProtect, and Defender was performing many useless computations while Firefox was generating many ETW events, resulting in an explosive combination that was using five times the CPU power compared to other browsers.
After the successful testing of the bugfix, it was delivered to the stable channel with updated Defender anti-malware definitions on April 4 (mpengine.dll version 1.1.20200.4). The bug was finally closed, and Mozilla developers stated that the fix would greatly improve CPU usage while browsing the web with Firefox.
Microsoft is also extending the update to obsolete Windows 7 and Windows 8.1 systems, as Firefox will continue to support the two operating systems until at least 2024.
Mozilla engineers stated that the new discoveries they made while analyzing the bug with Defender would help Firefox “go even further down in CPU usage” with all other antivirus software, not just Defender.
The recent update from Microsoft for its Windows Defender antimalware program is a crucial bug fix that significantly improves the performance of Firefox while browsing the web. It is great news for Firefox users who were experiencing high CPU usage issues for over five years.
With the update, Defender’s Real-time Protection feature will consume less CPU while monitoring the dynamic behavior of any program through ETW.
