Why no Intel i6 tri-core with hyper threading?

Didn't know weather to throw this here or in CPU since it's not really a CPU question, but...

How come intel doesn't have a tri-core with hyper threading to essentially have a hex core CPU? Surely there must be some on the die that fit this spec that they could have left alone rather than turning them into i3s.


I don't know where it would go though either above or below the i5.


Is it simply to have more i3s?

Well first off HT doesn't double cores. It just doesn't. A quad core with HT doesn't = an 8 core. And it doesn't really matter as the i5 fits in that price point. 

Hyperthreading only gives one core two threads for processing information faster, similar to if your head was a CPU core, but you had two mouths to eat more food than your normal friend who has one mouth. It was never meant to act as more cores.

As for no tri-core with hyperthreading, Intel really doesn't have a need to. A three core hyperthreaded processor would end up probably performing between an i5 and an i7, but there's not actually a whole lot of space there. The price difference is about $60-100 between an upper tier i5 and low tier i7 and the performance difference is only about 30% on synthetic benchmarks. If you make a processor that hits in the middle of the two it will only by about 15% faster than an i5 at most, but only $40 more could get you an i7. And if somebody is willing to spend that much on a processor I'm going to assume that they do things other than gaming, meaning that an i7 would make the most sense in that price range.

But surely a tri-core wither hyper threading would be a step above an i3.

It would be nice to have something like this for people who want more threads. Maybe they could have done that instead of so many i3 and i5 variations. Price point isn't an argument. Obviously prices would have to be adjusted to reflect the existence of an i6. But it's Intel. They don't like to innovate unless they really have to.

They need to make i9's a thing.

Wouldn't that have just be a true 8 core kinda thing? Something like what they recent came out with I'd recon. 

more like one hand feeding your one mouth compared to two hyperthreaded hands feeding one mouth

Because designing, testing and taping that out would be more money than it's worth in the end. Intel spends enough cash banging their heads against the wall pushing atom cpus to the mobile market.

i think its not possible, the way intel cpu´s are designed.

Only AMD can do this, because they work with CMT architecture. The FX6300 is your example there.

What is to stop Intel putting three cores in a die rater than even numbers like two four or six?

I understand AMD have the modules with '2' cores each but are Intel not all separate cores? And then hyperthreading enabled/disabled? 

Seems strange for it to just be impossible. I would like to know more.

Because they would need to re-design the whole chip then, because its not possible the way it is right now.

Hyper threading, you have 2 option, enabled or disabled, thats it. you dont have any more options for that, HT arent real core´s but just logical processors. Also the cache allocation would become a problem then.

AMD has real cores inside modules CMT architecture, with amd you have the abillity to simply disable individual modules.  THats the diffrence.

With intel i have 4 cores 8 threads, i can only disable HT then i get an i5, 4 cores 4 threads, or enable HT and disable 2 cores getting a i3 2 cores 4 threads. Or disable HT and disable 2 cores, then i get a pentium G, And thats it i dont have any more options.

 You dont have the capabillity to disable core's and threads individualy. only in pairs of 2. (as far as i know)

With AMD's CMT architecture its possible, because AMD has 2 "real" cores inside a module, those modules can be disabled individualy. So if i disable 1 module on a FX 8 core i basicly have  3M 6C real cores. FX6300.

I hope you get a bit what iam saying ☺

I don't think that Intel cares about lower end desktop processors at the moment. The i3 and the other dual core that they have its simple so they have something in that territory (think of it as the moon flag that just says that we have been there). 

Now they are only focusing on high end processors (may be i5s then i7s and xeons) and the low end laptop/ tablet territory. 

And yeah if they really wanted they could probably pull off something like this.

Yeah I think I got it. 

I knew it would take designing a new chip anyway, I was just wondering if there was some other oddity with I tel that stopped them from making odd numbered cores. 

Thanks.

5960X 8C / 16T, if i disable HT, then i basicly have 8C / 8T.

5820K for example is the same chip as the 5960X but just with 2 disabled cores, and that automaticly means, 4 disabled threads, because of HT.

If i disable HT on a 5820k, then i basicly get a real 6C / 6T cpu. As you can see, you only have the abillity to disable pairs of cores, not cores and threads individualy.

And thats basicly one of the reasons why AMD FX 8 cores are so nice vor virtualization at that price point, because of the CMT architecture.

Hi Mystery,

Just a minor point I would like to clarify for readers of this thread if I may :-)

The term 'simulated threads' is a little misleading as often people then believe it is just a hardware 'trick' that works at the OS scheduler level, or that for each real core there is also virtual core. It's not.

An i3 or i7 actually present 4 or 8 processors to the CPU - people often refer to these as 'logical processors'. As far as the OS is concerned the CPU has 8 processors (in the case of an i7). This is implemented by having two sets of registers and instruction queues for each execution core.

The above analogy of two hands feeding a mouth is therefore reasonable. The server (OS) sees two hands and can pass them work to do, but the mouth can only consume from one hand at a time. If you imagine a mouth being fed by a single hand then the time between the hand emptying its contents to the mouth to it getting the next item of food is wasted - and the mouth might get a break. With two hands the mouth does not get a break and the food is eaten a bit more quickly. 

The only exception is if you are running two processes, one integer based and the other floating point. In this scenario work can be executed on the FPU at the same time that the integer component is working on something else. 

This is all really clever stuff and quite fascinating. The mileage one gets from hyper-threading can vary enormously, which is why comments such as 'no games utilize hyper-threading' are often wrong:

I can set CPU affinity on my i7 against logical processors 0,1,2 and 3 (to utilize just physical cores 1 & 2) and get Unigine benchmark results almost as good as when work is scheduled against 0,2,4 and 6 (utilizing all physical cores). If I just use logical processors 0 and 2 (to utilize just physical cores 1 & 2 without HT)  the results are worse. Why? Because Unigine is optimal with 4 threads but does not push each logical processor to 100%; it can therefore benefit from HT and as far as Windows is concerned the 4 threads are being executed simultaneously. 

Occasionally two logical processors sharing physical resources is a good thing - a process with two threads working with the same data might actually be boosted if running on two logical processors which share the same execution core. No needing to fetch data from memory if it is already in the shared CPU cache might sound like a small boost but for some workloads it makes a surprising difference!

I really ought to put together a short blog on this with some graphics and facts to illustrate it as hopefully others would find it as interesting as I do :-D

 

Thanks for this extra addition. realy appreciate that.

You are right about the term "simulated thread" that could be miss understood. My appologies for that.

I do basicly mean the same thing, But i did not use an handy term, to make my self understandable i´m sorry..

indeed as far as the OS concerned, it still sees 8 logical processors, wenn we talk about an i7-4790K for example. Because we have 2 logical processors, per physical core. So "simulated thread" can sound a bit confusing for other people. you are completely correct. I have edited my post allready

Thanks for the head up! ☺

I would also realy appreciate if you could make a nice blog of this, i unfortunatly dont have the time for those sort of things. I think it would be very informative for averyone. To get more insight on  how it exaly works. This is a realy interessting informative study for eveyone.

Not sure about you, but I'm not paying 1k for an octa core. I'll get a 12 core Xeon. A real innovation would be a six core mainstream i7 at $320.

i7-5820K ??