why doesn't intel i5 core support multi threading?

[Aiswarya_121]

I was looking for technical differences between intel's i3, i5, and i7, and found out that i5, doesn't support multi-threading! This is quite absurd! Why would intel do that!?

 

[13thmonkey]

so that they have a differentiated product stack and can create the i7.

 

[ComputerSecurityGuy]

Yep, the i5 is the exact same chip as the i7. It just doesn't have HyperThreading enabled. And an i3 is an i7 -two cores and a Pentium / Celeron an i7 -two cores and HyperThreading. Xeon is a locked i7 with no iGPU. In other words all these chips start out as an i7 then are changed.

 

[synphul]

Like 13thmonkey suggested, to differentiate the i5 from the i7. It's not really absurd, by not including hyperthreading you get a true quad core cpu for much cheaper.

i5 4690k vs i7 4790k, $87 difference.
i5 6600k vs i7 6700k, $164 difference.

In short to allow you to buy a quad core for an average of $125 less than you'd be paying for it otherwise. At least when you move from a dual core i3 to quad core i5 you get 2 additional cpu cores (actual cores, not threading) for the roughly $100 price jump. Prices based on US pricing, may be different depending on currency, location and import/vat fees.

 

[Jaster_1]

1. You are confusing Hyperthreading with Multithreading.

https://en.wikipedia.org/wiki/Hyper-threading
https://en.wikipedia.org/wiki/Multithreading_(computer_architecture)

Multithreading is something all modern chips do. Hyperthreading is to increase logical core count over physical core. For example an I7 with Hyperthreading enabled offers 8 logical cores, 4 physical. An i5 does not have hyperthreading support so offers 4 logical cores and 4 physical cores. Some i3's with hyperthreading enabled offer 2 physical cores and 4 logical cores.

2. Intel CPU's are not the same "Then changed". It's called product binning.
https://en.wikipedia.org/wiki/Product_binning

Basically all start out as i7's however due to imperfect manufacturing process then most will fail the upper tier of binning. I5's have the SMT Hyperthreading support disabled. This is most probably down to them not actually functioning correctly off the production line. These features are then disabled and the chip is sold at the tier below. This continues down the stack to the bottom rung.

I see 2 people with Intel badges here and both have not explained correctly the answer to your question. This is why my job is getting harder and harder.

 

[13thmonkey]

1. You are confusing Hyperthreading with Multithreading.

https://en.wikipedia.org/wiki/Hyper-threading
https://en.wikipedia.org/wiki/Multithreading_(computer_architecture)

Multithreading is something all modern chips do. Hyperthreading is to increase logical core count over physical core. For example an I7 with Hyperthreading enabled offers 8 logical cores, 4 physical. An i5 does not have hyperthreading support so offers 4 logical cores and 4 physical cores. Some i3's with hyperthreading enabled offer 2 physical cores and 4 logical cores.

2. Intel CPU's are not the same "Then changed". It's called product binning.
https://en.wikipedia.org/wiki/Product_binning

Basically all start out as i7's however due to imperfect manufacturing process then most will fail the upper tier of binning. I5's have the SMT Hyperthreading support disabled. This is most probably down to them not actually functioning correctly off the production line. These features are then disabled and the chip is sold at the tier below. This continues down the stack to the bottom rung.

I see 2 people with Intel badges here and both have not explained correctly the answer to your question. This is why my job is getting harder and harder.

your job?

And true I misread multithreading for hyperthreading, but I believe that HT is what is being asked about.

Linking to a disambiguation page on wikipedia... did you read the page, do you know what it says, nothing is what it says.

And my answer is perfectly correct, an i5 with HT is an i7, and there is a difference for product differentiation reasons. Whether they are purposely made or binned is irrelevant. They can charge more for more features, and giving it a different name is a lot better than the old PIV days.

 

[Jaster_1]

"your job?

And true I misread multithreading for hyperthreading, but I believe that HT is what is being asked about. "

But descerning between the 2 is a must for answering the question. My Job. I'm a technical research and development co-ordinator for a well known institute. Can't say more then that I'm afraid.

 

[13thmonkey]

"your job?

And true I misread multithreading for hyperthreading, but I believe that HT is what is being asked about. "

But descerning between the 2 is a must for answering the question. My Job. I'm a technical research and development co-ordinator for a well known institute. Can't say more then that I'm afraid.

And you linked to a disambiguation page about it, well done.

The question is actually about HT, as that is the differentiator, and the i5 does support multithreading. So the answers are still correct, unless you can point out where we are wrong.

 

[Jaster_1]

"And my answer is perfectly correct, an i5 with HT is an i7, and there is a difference for product differentiation reasons. Whether they are purposely made or binned is irrelevant. They can charge more for more features, and giving it a different name is a lot better than the old PIV days."

They are never purposefully made. Haven't been in a long long time. If yields are good prices come down and are still sold at the designated tier. When yields are low prices go up and the lower tiers are priced accordingly. Prices are set by yields per wafer. Same has been true of all semiconducter manufacturing since the 80's.

Binning and product rating is the core of all CPU and GPU manufacturing otherwise we would all be paying astronomical amounts for the manufacturers to recoup costs on a per wafer basis as most do not hit the upper tier standards. Yields do increase over manufacturing time due to manufacturing fine tuning however runs between generations means that these become moot over a short term.

 

[13thmonkey]

So you are saying that they create differentiation to consume chips.
I say that they create & use differentiation to allow for different pricing.

If 100% of the chips were perfect, would they only sell i7's, I suggest that no they wouldn't they'd end up making a simpler, smaller chip and call it an i3, and they'd sell it for cost + profit, and sell the i7 for cost + more profit. The higher performing product will have a greater cost, that is typically disproportionate to the performance increase. This creates diminishing returns of cost vs performance, but maintains the halo around the top end.

It's two sides of the same coin, and doesn't actually help the OP understand why the i5 doesn't have HT. It's simply that they want to charge more for more features.

 

[Jaster_1]

Not all wafers are manufactured to i7 standards. Not all are mainstream CPU's. As production refines different architecture is used. Hence why you see Pentiums on current sockets. To recoup design costs of years gone by. For further reading I'd advise reading this

http://smithsonianchips.si.edu/ice/cd/CEICM/SECTION2.pdf

But paramount is binning and yield per wafer. If they have a high yield on a high end piece of silicon and an abundance in that market tier then they will reduce pricing accordingly based over all other factors (testing, manufacturing, design etc). A great example is how AMD binned higher spec 8350 for the 9xxx series and started them off at a whopping £500. Look at current pricing. Because they know they have to remain competitive against the other products in there lineup.

 

[13thmonkey]

To answer the OP's question, because they can, and because they can charge more for HT.

What's wrong with that answer.

 

[Jaster_1]

If i was to be facetious. In response to the OP's question ....

"All modern CPU's have multithreading. Are you sure you don't mean Hyperthreading? If it was hyperthreading then I would advise learning about product binning and profitability in terms of silicon per wafer".... 😉