Hardware Processor Cores / Threads

[N_Molson]

This is from my system, I wonder why the processor is displayed 8 times. I'd understand 4 times, because it has 4 cores, but 8 ? It has 8 threads, is Windows 10 displaying those ?

 

[Urwumpe]

Its because of Hyperthreading, a feature of all modern CPUs.

Because contemporary CPUs have a very long processing pipelines with many stages and many unique resources in those stages, they can pretend to have one and a half cores - with hyperthreading making use of multiple pipelines using those resources to speed up processing. Of course, its no true full second core, because those processing resources (ALU, FPU, MMU, etc). are still not existing multiple times - or at least less often as there are parallel pipelines.

For example, while pipeline 1 is doing an integer calculation, pipeline 2 could be doing a jump or a floating point calculation at the same time.

 

[N_Molson]

Its because of Hyperthreading, a feature of all modern CPUs.

That's it. Virtualization. I knew it at some point, but forgot about it. ?

I remember you have to be sure that feature is enabled in the BIOS to play with Virtual Machines, which I don't use currently.

 

[Fabri91]

No, virtualization has nothing to do with it.

As Urwumpe said it's hyperthreading, a feature present on many modern CPUs that helps with parallel workloads (though not as much as having a "real" second core).

 

[Urwumpe]

No, virtualization has nothing to do with it.

As Urwumpe said it's hyperthreading, a feature present on many modern CPUs that helps with parallel workloads (though not as much as having a "real" second core).

Well, strictly speaking it is a kind of virtualization in hardware. The resources of the CPU are shared and multiplied to the execution pipelines.

 

[Fabri91]

Got it. Still, almost any modern system has toggles in its UEFI firmware for both Hyperthreading (from what I've seen always enabled by default if supported by the installed CPU) and for the AMD or Intel "proper" virtualization technology used for VMs and such which on a number of motherboards, including mine, is curiously disabled by default.

 

[Urwumpe]

Got it. Still, almost any modern system has toggles in its UEFI firmware for both Hyperthreading (from what I've seen always enabled by default if supported by the installed CPU) and for the AMD or Intel "proper" virtualization technology used for VMs and such which on a number of motherboards, including mine, is curiously disabled by default.

Yes, its different levels and kinds of virtualization. One virtualizes only a processor core. The other a full hardware. You could also do that on the operating system level - that is what containerization like Docker does.

 

[hughesjs]

Well, strictly speaking it is a kind of virtualization in hardware. The resources of the CPU are shared and multiplied to the execution pipelines.

Sorry, I've got to disagree with you there... Hyperthreading isn't virtualisation, it's a dataflow optimisation technique. There's nothing virtual about it, it just makes heavy use of processor pipelining. By way of credentials, I'm an embedded systems engineer and I've designed CPUs in the past.

That being said, it doesn't really matter... I am arguing over semantics here.

 

[N_Molson]

Interestingly, I extracted the CPU earlier today because it recently reported overheating. Turned out it was time to replace the thermal paste, that sort of turned solid over the years. Those i7 can heat quite a lot. It feels weird to have something so small, costly and powerful in the hand. Like jewelry, but it doesn't (only) looks good, it actually does quite a lot of stuff. Also dismounted, bathed and dried the whole (cheap) aluminium radiator, of course the fan blades, removed former paste leftovers with a mix (drops) of water and toothpaste on the flat side, worked very well. Used one medical sterilized compress to clean the thing, the cloth is made so that it doesn't leaves fibers in the wound. Applied a generous layer of new paste, ran a benchmark and I'm very happy with the temp readings (and, needless to say, the stability) I got. So far, so good !

 

[Fabri91]

Also, keep in mind that the actual silicon "active" part usually is much smaller than the external heatspreader used on most desktop CPUs.