Hyperthreading help

[lucifersam]

They don't have half of a CPU. That was just the way things were simplified to people back in the day.

HT works by tricking the OS into thinking there are two CPUs on which to schedule threads. The CPU takes those two threads and executes them, more or less, concurrently. The P4 Netburst architecture's long pipeline design lends to HT because the pipelines are rarely ever full. When the pipeline isn't full for thread one, then it can give the spare pipeline slots to thread two.

That basically is how HT works. It shares the CPU's execution units, because in Netburst they are rarely ever fully utilised by one thread.

In a CPU there are parts of core that are always used by the the CPU while calculating an instruction and then parts that are not used so often. The way HT works is by taking the parts of the CPU that is used by every thread and having two of them while the other 90% of the CPU that is not always used is left single, hence they can calculate 2 threads at once. If it was as simple as tricking the OS into thinking there were two cores then software hacks would be abound to allow the non-HT cores to emulate 2 cores

 

[NathanE]

In a CPU there are parts of core that are always used by the the CPU while calculating an instruction and then parts that are not used so often. The way HT works is by taking the parts of the CPU that is used by every thread and having two of them while the other 90% of the CPU that is not always used is left single, hence they can calculate 2 threads at once. If it was as simple as tricking the OS into thinking there were two cores then software hacks would be abound to allow the non-HT cores to emulate 2 cores

I just clearly explained how it works... take it or leave it

 

[carlosvr6]

Thank you everyone for your help.

This is the reply i got from Intel:

An Intel(R) processor with Hyper-Threading Technology will be able to perform tow threads almost at the same time, while the processor without Hyper-Threading Technology will be able to perform only one thread at the same time.
Please keep in mind that the software that you are running needs to be designed to support Hyper-Threading Technology. If you need to know if the software is designed to support Hyper-Threading Technology, I would recommend you to contact the software developer.

I will put everything forward now to the Deputy Head and he can discuss it with the supplier.

 

[Dr_Evil]

Best thing for them is to come over and inspect the problem then give you a solution how to fix this. Best thing is to get it fixed, as the computers are already in use and you don't want to be further inconvenienced. If they can't fix it on-site, they'll have to replace it. You should be able to claim some money back for the inconvenience caused by this, as the PC's should have been tested properly before being shipped to you.

 

[Roughneck]

in device manager are they listed as


ACPI Multiprocessor Devices?

 

[NathanE]

ACPI Multiprocessor, yup.

 

[Darg]

If you have any 3D rendering software installed on them then it should be a simple matter of rendering with using threads and rendering without using threads and compare the results. While using threads in the software you must have course have hyperthreading enabled in the bios.

If you don't have any 3D program installed then download blender from www.blender3d.org

This is a freeware 3D modelling, rendering and animation program that rivals the big commercial products for functionality. If you need help setting up a scene to render then I can send you a blender file that you can open and render. There is a button that enables or disables threads so you can perform the comparison without having to change the hyperthreading settings in the bios.

I ran a test on using threads and not using threads on my old P4 3.0ghz HT machine. Using threads decreased rendering times by about 30% if not more.