Disable ht vs disable core

[Giggitygoebbels]

What is the performance difference?i dont want answers saying both are foolish.just want to know which save more power even if meagre and which performs better even if it is a tiny bit.thanks in advance.

 

[lazyboy947]

HT does add power usage, but not alot, best performance i would disable HT, and keep all cores active, but disabling cores would prob get u the most power savings. But not everything uses HT, and if its an i3 it would be pointless to disable cores, an i7 should do ht off, or ht enabled and disable one or two cores, two cores would basically make it an i3 and a waste of an i7.

disabling HT basically makes an i7 a i5, and a i3 a Pentium. But disabling HT would be best option for performance and power usage.

A good way to test would be to use something that monitors the wattage going to the pc from the outlet with core or HT disabled.

 

[Giggitygoebbels]

HT does add power usage, but not alot, best performance i would disable HT, and keep all cores active, but disabling cores would prob get u the most power savings. But not everything uses HT, and if its an i3 it would be pointless to disable cores, an i7 should do ht off, or ht enabled and disable one or two cores, two cores would basically make it an i3 and a waste of an i7.

disabling HT basically makes an i7 a i5, and a i3 a Pentium. But disabling HT would be best option for performance and power usage.

A good way to test would be to use something that monitors the wattage going to the pc from the outlet with core or HT disabled.

I3 does become a pentium,but i7 will become a xeon e3-1220(v2)(v1)
Because i7 has 2 more mb of cache.

 

[Giggitygoebbels]

Also if i disable a core on an i3, will it have 3 or 2 threads?
When i disable cores on i7, do i still get the 4 ht threads?

 

[geofelt]

It might make sense to disable hyperthreading. The rationale would be that you could overclock the cores higher.
And... you would avoid the problem of the os dispatching important work on a slower hyperthread.

Hyperthreads use residual cycles of the main core. Performance is about the equivalent of 1/4 of a full core.

I don't know that you could disable a single hyperthread, I think it is all or none.

And if you disable a core, I would think the associated hyperthread will be gone too.

 

[Giggitygoebbels]

If lets say i underclock my i3 or i7 to 1.6ghz,does the hyperthreads use the rest or only a quarter of the 1.6ghz?

 

[geofelt]

If lets say i underclock my i3 or i7 to 1.6ghz,does the hyperthreads use the rest or only a quarter of the 1.6ghz?

What are you trying to accomplish?

If you underclock, then everything just operates at a lower frequency.
The usual rationale for underclocking is to reduce heat and it's associated issues.

 

[lazyboy947]

Well if u have an i7 i know u didnt want this but ur never specified the cpu ur using, but itd be a waste of a $300 cpu to underclock and disable cores it

 

[Giggitygoebbels]

What are you trying to accomplish?

If you underclock, then everything just operates at a lower frequency.
The usual rationale for underclocking is to reduce heat and it's associated issues.

Reduce heat.increase stability.but does the hyperthread use the remaining (originalGHz-1.6GHz)?
Or it is only 0.4GHz?

 

[geofelt]

If you want to reduce heat, buy a low power chip version in the first place.
It really is not that important; the 22nm intel chips run cool at stock speeds.
They are stable at near 100c.

The cpu will automatically downclock itself when there is no work to do.

 

[Giggitygoebbels]

If you want to reduce heat, buy a low power chip version in the first place.
It really is not that important; the 22nm intel chips run cool at stock speeds.
They are stable at near 100c.

The cpu will automatically downclock itself when there is no work to do.

My friend have a sandy bridge core i3 2100 file server and with the stock heatsink,it overheats crazy after 4 days online.He plan to make it run stable for at least 7 days,before giving it a day to rest.

 

[cjl]

It really shouldn't overheat, even with the stock heatsink. Are you sure the heatsink is mounted correctly? That's what I would check first...

 

[lazyboy947]

aftermarket cooling, if ur doing a server if its not a server case or low profile ur problem is solved

 

[Giggitygoebbels]

It is installed properly noly that his house is very hot.

 

[Giggitygoebbels]

Best answer selected by Giggitygoebbels.

 

[sarinaide]

In actual testing HT amounts to about 10-15% of a true core performance. You can disable HT leaving physical cores, but you cannot disable physical cores and run HT virtual cores alone.

ie: i7 3770 4cores+4HTT if you disable a physical core you will have 3cores/3 HTT and so the cycle continues.

 

[geofelt]

It is installed properly noly that his house is very hot.

The intel pushpins are notoriously difficult to mount properly.
Look at the back of the motherboard to verify that all 4 pins are completely through the motherboard and locked.
If you remount, you need to clean off the paste and apply new.

 

[cjl]

Even in a hot environment, a stock speed Sandy Bridge really shouldn't overheat. I would double check that it is mounted properly.