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Firefox engineers discover a Windows Defender bug that causes high CPU usage

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41–50 of 223 posts

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#41
Is Windows Defender even worth enabling?

It eats up a lot of CPU. It doesn’t seem like much help in a default update enabled system where you are using a regular user account instead of an administrator account.

In addition, anti-virus and real time scanning is itself potential surface area for an exploit (for example a few years back there was an exploit based on Norton antivirus email scanner).

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#42

> a ~75% CPU usage reduction was noted when browsing YouTube in Firefox I wonder how many of the people who say "Firefox is significantly slower than chrome" are using windows... On my computer, Firefox IS slower than chrome but (with ad blockers enabled) by an insignificant amount. By still being "the last remaining mostly independent, maintained and reasonably popular browser" I'd prefer it to use over chrome even…

On my base M1 MacBook Air FireFox is noticeably slower than Chrome/Edge/Safari.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#43

This just reminds me of constant "things worked so fast on my Windows 95 machine back in the day with 16MB RAM". Meanwhile any piece of software could crash your PC and it did so regularly (I still keep spamming save in software because of those days) and internet was a pandoras box. I wonder how much overhead in modern OS/PC user experience comes from security/stability abstractions and tools.

>(I still keep spamming save in software because of those days)

muscle memory prevents me from being able to type a semicolon without cmd-s being the very next keys typed.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#44

I've experienced a bug related to the on-disk real-time scanning of Windows Defender, but instead with 100% disk bandwidth usage for unreasonable amounts of time. I purchased a license of a proper antivirus software to avoid that bug and the performance issues gone away. When you install another AV software, Windows Defender steps down and leaves scanning to the 3rd-party security solution. I selected one of the most…

> I purchased a license of a proper antivirus software Which is that? For years (and come to think of it, this goes back to the 2000's or even 90's), AV / antimalware software comes across as scareware, using tricks to ensure you're afraid of not having it. And second, who here has ever had a virus in the past ten years?

I agree AV software is essentially useless malware, but as to "who here has ever had a virus..." - well - the botnets are running somewhere.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#45

Earlier quoted context omitted.

Funny how that sort of thing can work out. I was involved in an industrial optimization company years ago. Microsoft came out with power-save features in their new release. The staff at a metal-recycling company we were installing at, started complaining that the furnace would stop optimizing overnight. We investigated. The controller computer would go into power-save mode, which suspended our control app. So the fur…

> It would literally have been better if they'd never invented power save mode. Only if you considered the purpose of power-saving mode to reduce total energy usage, vs to reduce amount of power (and consequent wear & tear) an individual machine uses. However that MS would release a feature like that which automatically kicks in on upgrade without any sort of consideration of what the machine was used for - it could…

>it could be running life-support systems!

i shudder at the thought that a critical piece of life-support anything would be running a windows based OS.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#46
Windows Defender is a long standing bug in the Windows operating system. ;)

My impression is that its invention was for the sole purpose of eradicating the idea that Windows is insecure and prone to viruses, which explains why it can be overzealous and CPU hungry.

I would only enable it for family members who don't know what they are doing. For some reason, I haven't needed any form of active virus scanning in something like 15 years. If it turns out I've been infected this entire time, the criminals sure are taking their time stealing my money, etc.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#47

> a ~75% CPU usage reduction was noted when browsing YouTube in Firefox I wonder how many of the people who say "Firefox is significantly slower than chrome" are using windows... On my computer, Firefox IS slower than chrome but (with ad blockers enabled) by an insignificant amount. By still being "the last remaining mostly independent, maintained and reasonably popular browser" I'd prefer it to use over chrome even…

On my base M1 MacBook Air FireFox is noticeably slower than Chrome/Edge/Safari.

Strange, I have the same laptop on a fast network and I can't tell the difference.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#48

I've experienced a bug related to the on-disk real-time scanning of Windows Defender, but instead with 100% disk bandwidth usage for unreasonable amounts of time. I purchased a license of a proper antivirus software to avoid that bug and the performance issues gone away. When you install another AV software, Windows Defender steps down and leaves scanning to the 3rd-party security solution. I selected one of the most…

> I purchased a license of a proper antivirus software Which is that? For years (and come to think of it, this goes back to the 2000's or even 90's), AV / antimalware software comes across as scareware, using tricks to ensure you're afraid of not having it. And second, who here has ever had a virus in the past ten years?

Indeed, I wouldn't install anything from McAfee if you paid me too, given the way it automatically installs itself along with various other unrelated applications and the number of phishing emails claiming to be from McAfee (which presumably exist because their creator is aware of how often McAfee itself pushes similar messages out).

I can't actually remember the last time any anti-malware software (built-in or otherwise) actually detected anything like a traditional virus, but there are plenty of computer users who are rather more trusting of links (including ones that download executables) in emails and the like. I don't doubt if I used a machine with all protection turned off and with the level of caution of a typical non-technical user it'd be hit with malware sooner or later. Most likely a browser plugin capable of reading passwords as I type them etc.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#49

I've experienced a bug related to the on-disk real-time scanning of Windows Defender, but instead with 100% disk bandwidth usage for unreasonable amounts of time. I purchased a license of a proper antivirus software to avoid that bug and the performance issues gone away. When you install another AV software, Windows Defender steps down and leaves scanning to the 3rd-party security solution. I selected one of the most…

> I purchased a license of a proper antivirus software Which is that? For years (and come to think of it, this goes back to the 2000's or even 90's), AV / antimalware software comes across as scareware, using tricks to ensure you're afraid of not having it. And second, who here has ever had a virus in the past ten years?

> Which is that?

I purchased a license of ESET Internet Security, and full disclosure: back in early 2017, I worked at an ESET-licensed reseller as a Presales and Support Engineer, so I know how to fine-tune it and all the ins and outs.

By nature, it's very lightweight (330 Mb RAM footprint), but you can fine-tune it even more if you want.

> And second, who here has ever had a virus in the past ten years?

We the people at HN are tech-savvy and of course will not get infected, but recently I spotted malware out-in-the-wild via Facebook Ads[0].

Your usual grandma/grandpa using the computer to connect with loved ones and play Candy Crush Saga will get infected, if they are not by now.

Some people tell me: "bUt tHaT'S BeCaUsE ThEy aRe vIsItInG WeIrD SiTeS," well, even if you stick to the common social media sites and usual news sites, you will get infected.

I cannot emphasize this enough, but you're responsible of your own computer so I will not proselytize you into purchasing AV software.

--

[0]: https://twitter.com/IvanMontillaM/status/1604308301579051009

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#50

Is Windows Defender even worth enabling? It eats up a lot of CPU. It doesn’t seem like much help in a default update enabled system where you are using a regular user account instead of an administrator account. In addition, anti-virus and real time scanning is itself potential surface area for an exploit (for example a few years back there was an exploit based on Norton antivirus email scanner).

Windows Defender is worse than nothing but in recent versions of Windows it is enabled by default, very difficult to disable, and may get re-enabled at any future software update.
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