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Fans run watching video, but don't when using Safari

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I am curious as to why the silverlight plugin ramps the fans up (3k+ rpm) when I am watching prime video's in Firefox, but when watching the same video's in Safari, the fans a pretty much the standard 2000 (2k - 1.5k) rpm. Happens with youtube too. Safari and web videos is way quieter and I guess I just don't understand why the difference.

Is there a way to get FF to throw a little less power at these video's so as to not light the fans off so much? It can really drown out the video audio depending on what it is. As it is, I use Safari for watching video's, but hate having to have 2 browsers open.

I am curious as to why the silverlight plugin ramps the fans up (3k+ rpm) when I am watching prime video's in Firefox, but when watching the same video's in Safari, the fans a pretty much the standard 2000 (2k - 1.5k) rpm. Happens with youtube too. Safari and web videos is way quieter and I guess I just don't understand why the difference. Is there a way to get FF to throw a little less power at these video's so as to not light the fans off so much? It can really drown out the video audio depending on what it is. As it is, I use Safari for watching video's, but hate having to have 2 browsers open.

All Replies (3)

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Firefox, and the plugins, have no control over the fans. In most cases, they are auto-controlled by thermostats in the computer.


Also, you are talking about two different programs. While they do the same job, they work differently.


Are the fans kicking up once in a while, just with the video? Do you have a display showing the temperatures of your system? What about a CPU monitor? What are they showing?


I had a similar problem. My computer temps were heating the case so much it tried to burn my hand. Turned out the cooling vents were clogged.

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Well, I was just into my macbook not long ago changing out the battery and the key board. The back light stopped working on mine in places.

Either way, I know its clean, because I actually had the opportunity to check it.

I have XRG 1.7.3 that I use to watch the temps and stuff like fan speed.

Safari running the videos uses a good amount of CPU (~70% - 90%) and CPU die temp of 71C, where Firefox will run the CPU clear up to the 150%+ range and a die temp of 85+C. The second I stop the video, I see the case temps (sensor1,2,3) start to drop pretty quickly. Is there a different version of Silverlight for firefox that is different from Safari's? I'm stuck with Silverlight for the Amazon Prime stuff.

Pretty much, video in Firefox sends the case temps to somewhere around 39-42C, nothing crazy, but with the die temps, enough to kick the fans up to the 3500-4000 rpm range watching the videos.

Safari on the other had shows case temps around 30-32C and fans that sit steady at 1999- 2048 rpm watching the videos.

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Yes there is a different version of Silverlight for Firefox, and Internet Explorer uses a different version, too. Only Safari and Chrome might use the same version, because they are (or were since Chrome went to Blink) both based on WebKit.