Hyperthreading GUI??

[eoniverse]

Not sure where to place this question so mods please feel free to move it.

Hyper threading: I have it. I like it and I use it....just not all the time. I render and appreciate what it offers. But...we all know it raises temps and impacts - to varying degrees an overclock.

Question: Does anyone know if there is software on the desktop side to turn on hyper threading if I leave it off in the BIOS? That way when I'm not rendering the system can run cooler? And when I do need it... I don't have to reboot into the BIOS to turn it on.

I've looked but don't see anything other than ways in msconfig to turn off some of the processors but that doesn't provide the flexability I am looking for. But maybe I've missed it.

Would anyone know if there is software that accomplishes this?

I'm on Windows 7 pro, Asrock x58, i7 920 DO @ 4.09 @ 1.275 (If it means switching M/B or chipset....I believe it may be worth it)

 

[BrightCandle]

No way that I know of. Windows is kind of partial to knowing how many CPUs there are at boot and that staying the same while it's running.

Bare in mind in later models it has much less impact on thermal and overclocking limits so on a more modern CPU it doesn't need to be turned off. Was a problem limited to the c and steppings of that processor (1155 as well presumably?)

 

[brandonb]

I believe (someone correct me if I'm wrong) this is a windows kernel limitation. I believe windows has to boot with x number of cores and cannot be changed once running.

With Virtual Machines its the same thing. You have to set the # of cores before booting the windows system. You cannot change them dynamically after the system boots.

 

[Prey2big]

Several games does not use "hyper-threads" at all.

 

[BrightCandle]

I think Linux could cope with it as it supports the very big mainframe like machines that can potentially have parts replaced while the system is running but I haven't seen such support used for hyperthreading. So I don't know of a normal os that does support changing the CPU count after boot. So yes its a limitation of windows but also don't think there is an alternative that does support it.

 

[SPBHM]

I would assume that, if you are not loading the CPU enough to care about HT, the added power usage from HT would be irrelevant anyway...

you can always set affinity to the real cores only.

 

[sm625]

Hyper threading: I have it. I like it and I use it....just not all the time. I render and appreciate what it offers. But...we all know it raises temps and impacts - to varying degrees an overclock.

...

That way when I'm not rendering the system can run cooler? And when I do need it...

whoa whoa whoa stop right there at the "runs cooler" part. I believe your logic is flawed. If you're not rendering or doing anything else that is cpu intensive, then HT isnt going to raise your temps or power draw to any significant degree. The only time HT actually does rasie your temps and your electricity bill is when you are stressing the cpu, and you have stated that is when you want the extra performance. So you arent going to see any difference at all by disabling HT for low loads and enabling for high loads.

The only way for you to actually save watts is to switch to a haswell 4C/8T chip. But then you're still spending money, even moreso. You would have to render for 24/7 for at least 2.5 years straight (or more if you cant get AVX+ compatible binaries) in order to justify the cost of upgrading just for the sake of power saving.

 

[taisingera]

The only thing I could recommend besides having hyperthreading enabled in BIOS is go to Run msconfig, under Boot tab your os is highlighed, and click on Advanced Options. There you see Number Of Processors, check that if it is not, and put the maximum number from the drop down menu, then Restart Windows.

 

[BrightCandle]

On the i7 920 hyperthreading was worth at least 10C for me and around 200Mhz of overclock. I couldn't get above 3.8 with HT on but with it off I could achieve 4.0. This was a common occurrence with these CPUs. It was one of the trade offs I made back then, I went for HT off as very few things benefited. Today I think that is still largely true.

 

[eoniverse]

Thanks everyone for clearing that up. I'll benchmark some to decide about leaving it off or on. Was trying to avoid that effort. Completely understand that reason why there is no software available to do this. Appreciated

 

[Zodiark1593]

On the i7 920 hyperthreading was worth at least 10C for me and around 200Mhz of overclock. I couldn't get above 3.8 with HT on but with it off I could achieve 4.0. This was a common occurrence with these CPUs. It was one of the trade offs I made back then, I went for HT off as very few things benefited. Today I think that is still largely true.

In my tests on an i5-460M (2.53 GHz dual core Arrandale) Hyperthreading gave me a ~20% boost in video encoding and rendering. Since rendering is commonplace with me, there's no way I'll say no to free performance, even with heightened power use.