Super User
Super User

Questions tagged [hyper-threading]

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).

96 questions
61
votes
6 answers

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?
Gordon Gustafson
  • 2,217
51
votes
5 answers

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 are 2 threads per core, dividing the CPU in 4…
seriousdev
  • 1,340
49
votes
3 answers

What is the difference between hyper-threading and multiple cores?

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 there are two separate CPU usage graphs. I have a…
Josh Stodola
  • 927
43
votes
4 answers

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?
Mikhail
  • 1,481
  • 3
  • 15
  • 22
31
votes
3 answers

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 "CPU" below? Does (say) CPU 6 and CPU 7 below…
Charles Burns
  • 835
22
votes
3 answers

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 have 1000+ threads when my processor is only…
dpl47
  • 339
18
votes
3 answers

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 options) and disabling processors there, not sure if it…
Moab
  • 58,769
16
votes
3 answers

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 top, as one core of the virtual cores is completely…
dronus
  • 1,978
15
votes
2 answers

What is the difference between multithreading and hyperthreading?

I've heard the terms hyper-threading and multi-threading, but what exactly is the difference between them? What kind of Intel processor uses them?
rose
  • 167
14
votes
1 answer

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?
Ryan Dougherty
  • 243
12
votes
4 answers

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 is true) and that this may cause a performance…
Anthony
  • 265
12
votes
2 answers

How do I identify which cores are which on an Intel hybrid CPU?

I have an Intel hybrid CPU (Alder Lake). This means it has some number of P-cores, and some number of E-cores. Additionally, the P-cores are hyper-threaded. Task Manager, and other performance and temperature monitoring programs, report all these…
Bob
  • 63,170
12
votes
3 answers

Why Hyper-Threading provides 2 virtual cores but not more?

Here is an explanation of Hyper-Threading found on Wikipedia: For each processor core that is physically present, the operating system addresses two virtual (logical) cores and shares the workload between them when possible. I'm wondering why we…
A.L
  • 820
  • 2
  • 12
  • 29
11
votes
3 answers

Single Threaded Qaud Core v.s Hyper-Threading Dual Core

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, the 4 cores 4 threads should perform faster than 2…
David
  • 149
9
votes
2 answers

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 will run in a single core at 2.27GHz. Right? My…
GoUkraineGo
  • 2,171
1
2 3 4 5 6 7