A technology by Intel to increase processor throughput, by adding independent logical processing units in each core (and thus exposing two times the number of cores to the operating system).

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5answers
11k views

Why is my dual-core CPU recognized as a quad-core one?

My processor is an Intel Core i3-380m. As you can see, it's 2 cores and 4 threads. Although, both Ubuntu 11.04 and Windows 7 seem to think it's a quad-core CPU: Why is this? Is it because there ...
34
votes
3answers
20k views

Hyper-Threading and Dual-Core, What's the Difference?

In a conversation with the network administator, I mentioned that my machine was a dual-core. He told me it was not. I brought up the task manager, went to the perfomance tab, and showed him that ...
29
votes
4answers
7k views

How much speedup does a hyper thread give? (in theory)

I'm wondering what the theoretical speedup is from hyper threaded CPUs. Assuming 100% parallelization, and 0 communication - two CPUs would give a speedup of 2. What about hyper threaded CPU?
27
votes
3answers
13k views

What is hyper-threading and how does it work?

I've heard the term hyper-threading thrown around a bit recently, what exactly is hyper-threading and why is it important?
18
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3answers
8k views

How does Windows processor affinity work with hyperthreaded CPUs?

How does Windows processor affinity work with hyperthreaded CPUs? Let's use an example (pictured) of a system with four cores, each with a hyper-threaded virtual core. Which cores correspond to each ...
15
votes
3answers
4k views

Task Manager is saying the system is running with over a thousand threads

I opened up Task Manager and looked under the "System" area and saw: Threads: 1337 Since I have a dual-core processor with hyper-threading available (meaning four threads), how is it possible to ...
15
votes
3answers
28k views

Disable Hyperthreading in the Windows 7 registry

Some bios's Do Not have the option to disable Hyperthreading of the CPU, it there a way to disable it in the Windows 7 Registry? Or a tool or software? I know about msconfig boot tab (advanced ...
8
votes
2answers
2k views

Should I disable hyperthreading in an Intel CPU?

I have a laptop with Intel i5 M430 2.27GHz. The CPU has TWO REAL cores but it also has some kind of virtualization so Windows sees it as 4-core. In a REAL dual core CPU, a single threaded program ...
7
votes
3answers
15k views

What is the difference between multithreading and hyperthreading? [closed]

I've heard the terms hyper-threading and multi-threading, but what exactly is the difference between them? What kind of inlet processor uses them?
6
votes
1answer
9k views

Number of cores available to VMware Player limited to physical cores or hyperthreaded cores?

I have an i7 with 2 physical cores, because of hyper threading Windows 7 reports 4 cores (at least in the Task Manager). My question is, when allocating cores to a VM in VMWare Player is it taking ...
5
votes
2answers
17k views

How to query Intel® Hyper-Threading current state and how to enable/disable it?

How can I see if my Intel® Hyper-Threading is enabled or disabled on my Windows 7?? There is a way to change it?
5
votes
3answers
14k views

Single Threaded Qaud Core v.s Hyper-Threading Dual Core [duplicate]

Let's say we have two CPUs, One is Quad Core 3.2 Ghz with 4 Cores, and We have a Dual Core 3.2 Ghz with 2 Cores with 2 threads in each Core (Hyper-Threading). My assumption as a programmer will be, ...
5
votes
1answer
867 views

Why does my non-hyperthreading enabled CPU claim it has hyperthreading?

I was checking my processor for the aesni (hardware aes, "aes" flag) when I discovered the "ht" flag. This, on i7 processors denotes the CPU's ability to do hyperthreading, however, since I own a i5-...
5
votes
2answers
3k views

cpu load measure with hyperthreading on linux

How can I get the true usage of a multicore hyperthreading enabled cpu? For example lets consider a 2 core CPU, expressing 4 virtual cores. A single threaded workload would now show up as 100% in ...
4
votes
2answers
3k views

Hyper Threading vs Overclocking

What is the difference between these two, and under what circumstances would I want to implement them? Are there circumstances when I would only want 1 and not the other? According to Wikipedia, ...
4
votes
2answers
3k views

Is there a significant performance difference between virtual and real cores? [duplicate]

Possible Duplicate: Hyper-Threading and Dual-Core, What's the Difference? Most Intel processors feature what they call "hyperthreading," basically another virtual core for each physical ...
4
votes
2answers
10k views

CPU monitoring: hyper threading, current clock speed

I think it'd be interesting if it were possible to check out at how much Ghz each one of my cores is running. Is it possible, at all?
4
votes
3answers
2k views

Quad Core host with hyper-threading, how many processors to configure in VirtualBox?

I have a quad-core i7 processor with hyperthreading (8 logical cores), when I configured a virtual machine to use 8 processors, VirtualBox gave me a warning saying that I only have four cores (which ...
3
votes
3answers
2k views

How can a single threaded application like Excel 2003 take more than 50% of a hyper-threaded or dual-core CPU in task manager?

I'm waiting for Excel to finish a recalculation and I notice that the CPU usage as reported by Task Manager occasionally spikes to 51% or 52% on a Pentium 4 with hyper-threading. How is a single-...
3
votes
2answers
10k views

/proc/cpuinfo gives CPU info per core or per thread?

My CPU has 2 cores, so I can see two parts in /proc/cpuinfo. But, I want to know if CPUs that support Hyper-Threading (or similar tech), will /proc/cpuinfo give CPU info per core or per thread (or ...
3
votes
1answer
3k views

What are “hyperthreading” and “virtual cores”?

I'm new in this computer terms. So anyone can explain to me what "virtual cores" and "hyperthreading" are at greatest detail a layman can understand? People told me that virtual cores are imaginary ...
3
votes
1answer
1k views

Eclipse: would more CPU cores with HyperThreading help increase speed?

I'm programming a very large project in Eclipse. Right now I use a dual core machine with 2GB RAM, but Eclipse is sometimes busy for minutes (refreshing/indexing/building), so I'm upgrading to a new ...
2
votes
2answers
8k views

How to disable HyperThreading on Mac OS X Lion?

Unlike my old Windows Boxes and Linux Boxes, I do not have access of something similar to a BIOS on my MacBook Pro. I want to disable Intel i7's HyperThreading (so 4 cores look like 4 cores and don't ...
2
votes
1answer
1k views

Single-threaded program takes too low CPU?

I am using Windows 7 Professional, Intel i7 CPU. I know the i7 has Hyper-Threading and I assume this is the reason. While running a single-threaded program, I saw that it only uses 12-13% CPU in Task ...
2
votes
1answer
696 views

Does the i5 processor in the 2011 iMac allow hyper threading?

On the intel website, it says that the i5 processor uses hyper threading. Elsewhere on the internet I've read various conflicting reports. Can anyone give me a definitive answer?
2
votes
3answers
1k views

Running threads on a non hyper-threading Intel processor

Intel Pentium Processor E5700 (2M Cache, 3.00 GHz, 800 MHz FSB) does not have hyper-threading but it has has 2 cores so I am assuming it has 2 threads Now if I write a heavy number crunching program ...
2
votes
1answer
659 views

How to interpret this /proc/cpuinfo data?

I'm using Intel Xeon E5-2620 processor. These are something I'm confusing about. I'm using Linux and in /proc/cpuinfo it says model name : Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz According to the ...
2
votes
0answers
624 views

Disable hyperthreading on MacPro Xeon

We need to disable hyperthreading on several MacPros. We have just two types of Macs - Dual QuadCore 2.4 "Westmere" and single CPU SixCore 3.66 "Westmere". All machines run 10.6.8 For some strange ...
1
vote
2answers
448 views

do I get half the CPU speed for a single thread if HT is turned on? [duplicate]

If I have a single 2.6GHz core for example would it mean that with hyperthreading I have only 1.3GHz for a single thread that my app have or is it on demand only if I will use (lets say my app is the ...
1
vote
1answer
9k views

disable hyperthreading on a multi-core Dell PC

I have a Dell desktop running Windows 7 Professional. I think the processor is an Intel Core i7-2600 Recently a computer expert who specializes in Linux clusters was looking at my desktop PC and ...
1
vote
2answers
545 views

Running Ubuntu in VirtualBox under Windows 8.1 doesn't use CPU on 100%

I am running Ubuntu 14.10 64 bit under Windows 8.1 64 bit using VirtualBox 4.3.10. I have an Intel Core i5-2410M CPU, with 2 physical cores and enabled HyperThreading and virtualization. I have set ...
1
vote
2answers
1k views

Optimum number of threads to use for best parallel processing on an i5 [closed]

I'm interested in running some reasonably heavyweight processing on my desktop/laptop (not so bad that it requires a cluster, but needs a good home machine). My question is how many threads to create ...
1
vote
0answers
2k views

See if Mac OS X has enabled hyperthreading?

There is a way of disabling hyperthreading on Mac OS X: How to disable HyperThreading on Mac OS X Lion? Is there a Terminal command of seeing whether Mac OS X has hyperthreading enabled?
1
vote
1answer
2k views

VirtualBox recognise all threads as cores or only physical cores for dual core Core i7?

When I run VirtualBox (or other virtualisation software) it lets me select how many cores I like to allocate to a virtual machine. Since I have a dual core 2.66gHz Intel Core i7 with hyperthreading, ...
0
votes
2answers
461 views

Again about Hyper Threading

I have Asus 1025c with dual-core atom with hyper-threading enabled. When I play games, processor load rate always less than 25% (1 core). Is that means, that game (running single thread) occupies only ...
0
votes
2answers
780 views

Hyperthreading Calculating Load [duplicate]

I have a dual core core i5 with hyperthreading. Since hyperthreading allows for unused cpu time to be used by other processes, why would this make it seem like 4 logical processors (2 per actual core)....
0
votes
1answer
319 views

Does hyperthreading divide GHz in half?

Imagine you have a CPU with 4 cores @ 2.2GHz, each one with a thread. Therefore, the OS thinks that it has 8 cores @ 1.1GHz each (I think). What would be the maximum GHz that a not concurrent ...
0
votes
1answer
549 views

Core i3 3220 for gaming [closed]

Since the Core i3 3220 has Hyper-Threading, will games like Battlefield 3 see and use the CPU as a virtual "quad core" rather than just 2 physical cores, so that AI and other features in the game run ...
0
votes
3answers
1k views

Disable Hyper-Threading on Dell XPS L502x

Does anyone know how, or if it's even possible, to disable Hyper-Threading on an Dell XPS L502x? I've checked the BIOS, which seems like it's hiding a lot of the usual options, but can't see anything....
0
votes
1answer
354 views

What happens to HyperThreading when I throttle the state on battery power?

If I have a laptop with an i7 that I decide to throttle the maximum processor state to 50% on battery power, what happens in regard to HyperThreading? Does it get activated at 50% frequency? or does ...
0
votes
1answer
388 views

Full HD and hyperthreading

I have 3 GHz Pentium 4, and it's not best for playing full HD videos. I noticed, that when I'm playing full HD video, only 50% of my cpu is used, so only one of virtual cores is doing it's job on full ...
0
votes
2answers
182 views

Why is it said that 'The longer the pipeline, higher the processor clock rate' [duplicate]

I have been recently going through the hyper threading technology of Pentium 4. The number of pipeline stages is high in P4 and is said that it will increase the speed of clock rate. How is that ...
0
votes
1answer
34 views

Duplication of Architecture State means physically extra?

Hyper-Threading Technology makes a single physical processor appear as two logical processors; the physical execution resources are shared and the architecture state is duplicated for the two logical ...
0
votes
2answers
1k views

How to disable HT in a Intel Atom D425?

I can't find in the BIOS the option to disable HT. Is this a BIOS problem or the processor itself doesn't support running as a single core?
0
votes
1answer
24 views

CPU time count on HyperThreading systems on linux

I am trying to estimate the amount of work a multithreaded application takes. That is quite a simple task with real cpu/cores as I can just take the CPU time from proc and that will be an estimation ...
0
votes
0answers
20 views

How to turn off hyperthreading on hp z230 Win7 32bit

I have a legacy application that when ported to this new HP desktop exhibits performance errors. I need to disable hyper-threading on this desktop. It has an Intel I5-4095 quad core processor. The ...
0
votes
1answer
146 views

Turn off HyperThreading without BIOS

I need to turn off HyperThreading from my i5-3210 notebook since it hinders my IDE performance. My i3 took about 10+ seconds from compile to run in my Android VM, same code runs in my AMD in about 10 ...
0
votes
0answers
154 views

How do I enable hyperthreading on CentOS 6?

How do I enable hyperthreading on CentOS 6? I checked the flags field in /proc/cpuinfo and ht is in the flags section. Below is my processor information. ~$ lscpu Architecture: x86_64 ...
0
votes
0answers
506 views

Virtualbox with i7-4790 one thread per virtual machine

I’m considering buying an Intel Core i7-4790, which has 4 cores and 8 threads. With a 4 core, 8 thread CPU you should see 8 CPU available in the green slider area; see picture below. I set the ...
0
votes
1answer
54 views

Cores and threads - Performance

I wonder if a 4 core/8 thread cpu will perform better than a 4 core/4 thread cpu. If the answer is yes; How much better will a 4/8 perform? EDIT: What if its for running 4 single threaded apps? And ...