Does turning off hyper-threading reduce heat?

[ppara5]

Disabling turbo would reduce heat, albeit with a reduction in performance. But would disabling hyper-threading reduce heat?

I ask for two reasons. First, laptops aren't great at keeping processors cool. And second, reducing heat would allow turbo to run as much as possible (Yes, I know I'm trading off).

In case it matters, I'm specifically interested in Ivy Bridge.

[n_scott_pearson]

As well, with the Meltdown and (especially) Spectre issues outstanding, disabling HT avoids some of the side-channel attack vectors and thus represents another advantage of doing so.

You would think that disabling HT would reduce the heat, but remember that the processes running on the secondary HT threads would need to run on other Cores instead. This may eliminate most of the gain and might otherwise be possible. Try doing it and see if it differs in heat levels.

...S

[ppara5]

Thanks for the reply. Yes, there were actually three reasons, with the third being the many flavors of Spectre. I must admit, I could never understand why hyper-threading was of value, as the threads were going to run in one of the cores anyway, but I suspect Intel did a few benchmarks.

[n_scott_pearson]

Linux folks have indicated performance loss from disabling HT can be as much as 40%, so value proposition is significant -- if you feel safe using it, of course; Some Linux distros are disabling it by default.

...S