How many cores does a smartphone need?

[brmiller1976]

Think about it from a marketing perspective.

Customer: "Tell me about these two phones."

Salesman for Motorola: "This is the Motorola ATRIX MegaQuad XXL! It has FOUR cores. That's FOUR microprocessors for FOUR times the performance!"

Salesman for HTC: "This is the HTC 8X."

Customer: "How many cores does it have?"

Salesman for HTC: "Two. But two cores is more than enough. Let's look at this demo and at this performance curve chart which..."

Salesman for Motorola: "The HTC only has two cores! Our ATRIX MegaQuad XXL has FOUR cores -- twice the power, for the same price!"

Salesman for HTC: "But that's not technically tru..."

Customer: "I'll take the Motorola. Twice as much capability may come in handy, even if I never use it, for the same price."

 

[Simon Tupper]

Think about it from a marketing perspective.

Customer: "Tell me about these two phones."

Salesman for Motorola: "This is the Motorola ATRIX MegaQuad XXL! It has FOUR cores. That's FOUR microprocessors for FOUR times the performance!"

Salesman for HTC: "This is the HTC 8X."

Customer: "How many cores does it have?"

Salesman for HTC: "Two. But two cores is more than enough. Let's look at this demo and at this performance curve chart which..."

Salesman for Motorola: "The HTC only has two cores! Our ATRIX MegaQuad XXL has FOUR cores -- twice the power, for the same price!"

Salesman for HTC: "But that's not technically tru..."

Customer: "I'll take the Motorola. Twice as much capability may come in handy, even if I never use it, for the same price."

This is why I don't listen to salesmen, I go in a store, pick a windows phone tell him about it and I make it clear that I don't want a Motorola Razr even it's good...

 

[Gungzwei]

If there is a quad core Windows Phone available, and it doesn't eat battery apprecialbly faster than a single or dual core phone, I'll buy it over it's lesser core counterparts.

The reason being i'll most likely have it for 2 years like I have with all of my other phones. The OS will be able to manage 4 cores and once software/apps start to be written to take advantage of more cores, I will already have 4 cores.

Most programs still only use one cpu and still run in 32 bit, but it doesn't make me want a single cpu running at 1.21 jigawatts. It makes me seek out software that can take advantage of the hardware that is available.

A single CPU that has the ability to process as much data as 4 cores will likely generate as much or more heat as a quad. Same reason overclocking your CPU generates more heat and the reason why microwave ovens work. More mega/gigahertz isn't the answer any more than more cores. It's a balance. If gigahertz were the answer, AMD and Intel wouldn't have given up on the clock wars. I was a lot easier for marketing to throw a single performance number at people.

Developers aren't always effecient in the way they use the hardware, which is why it's so tempting to throw more of everything into a computer.

If you want to simplify it, this is how...
How many cores? It depends...

 

[a5cent]

@brmiller1976

Hello brmiller1976, assuming your analogy reflects present day sales tactics, then this is my take on it:

Motorola Guy: "twice the power, for the same price"

The Motorola guy is flat out lying, because in reality the quad-core is weaker than the dual-core under almost all circumstances (this statement applies to present day smartphone SoC's and nothing else).

HTC Guy: "Two. But two cores is more than enough.

This is where the HTC guy makes a stupid mistake. He shouldn't be talking about cores but about processing power. I'm sure you would want the Motorola guy to get called out on his lying, so what's the problem? Anyway, in your analogy the customer believes that "bigger numbers on a spec sheet must always mean better" and walks out having paid the same price for an inferior product (that will run his apps slower). Pretty bad if you ask me...

IMHO, it appears that you doubt a dual-core CPU can be faster than a quad-core CPU. All I can do is ask you to look at the benchmarks I've linked to in a previous post.

Surely there is a problem with my writing style, but your analogy hasn't helped me see it. I appreciate the attempt though. In this case I think it would be better to just speak plainly. I have no problem with people being direct.

 

[brmiller1976]

This is why I don't listen to salesmen, I go in a store, pick a windows phone tell him about it and I make it clear that I don't want a Motorola Razr even it's good...

Alas, you're quite rare, as WP sales illustrate. The average consumer goes in with only a vague sense of what he or she wants, and is "navigated" towards something that fits the carrier's agenda (and the sales rep's agenda), with the exception of Apple products.

Apple's also helped by having its own stores -- if you want an iPhone, you can skip the whole "buy a Droid/Evo/whatever" pushy sales spiel and just buy your phone with your preferred carrier at Apple retail. That's an important reason why Microsoft should grow its sales presence.

 

[Reflexx]

That's why many of us believe that there should be a strong marketing and campaign push focused on performance instead of specs. If customers can be led to look for performance, then fancy sales speak about specs won't be as relevant.

Smoked by Windows Phone was just the start. There needs to be more of this type of campaigning.

 

[a5cent]

@Gungzwei

Hello Gungzwei, I agree with most of what you said, but we differ on two counts:

Most programs still only use one core <snipped>, but it doesn't make me want a single core cpu running at 1.21 jigawatts. It makes me seek out software that can take advantage of the hardware that is available.

That is certainly a good approach, but it won't always work. The very first thing I attempted to explain in this thread is that it isn't always economically/technically feasible to distribute an apps computational load across an arbitrary number of cores. It's not simply that developers are to blame for "not being efficient in the way they use hardware".

For many smartphone apps you would be hard pressed to find a way to make good use of two cores, and making use of any core beyond the second becomes increasingly difficult. There is only so much you can do with certain types of software to better adapt them to multi-core CPU's. At some point you need to start thinking about the opposite approach... how to better adapt the hardware to the software that customers want to run. Do you doubt this?

It is much easier to find desktop applications that can make good use of more than two cores, and Intel could easily give us desktop CPU's with 16 cores, but we are still only at four. Why? Server, desktop and smartphone software differs, and the hardware we use in those environments should reflect those differences.

A single core CPU that has the ability to process as much data as 4 cores will likely generate as much or more heat as a quad.

Generated heat doesn't have much to do with the number of cores in a CPU. Rather it revolves around the number of transistors that went into building the entire CPU, how many of them are active (applied current), how those transistors are built (materials and node) and clock frequency.

A desktop CPU with twice as many cores will usually have about twice as many transistors, have a higher TDP and cost more. For mobile CPU's that is not true! Due to thermal and power limitations all high-end mobile CPU's built at a similar node (28nm - 32nm) use a similar number of transistors, have a similar TDP and cost about the same. Whether or not those transistors are invested into two or four cores won't change thermals much, unless most of those cores remain idle which isn't our goal. For this reason, high-end mobile CPU's, where price is less of an issue, will (for the foreseeable future) make us choose between fewer high-performance cores or more lower-performance cores. Based on the types of software we run on our smartphones, the former is the better choice.

I don't have a hotline to Samsung's SoC developers, but I'm certain the things I've mentioned above are part of the reason why the iPhone 5 and Samsung's next high-end Exynos SoC will both be dual-core and not quad-core offerings. According to your logic, at least how I understand it, they should be going quad-core, but they aren't.

 

[Gaichuke]

Amazing stuff, a5cent. Just amazing.

Your posts have been the best versed explanations about the irrelevance of core count in smartphone industry I've ever read. This thread should be mandatory read for everyone.

I really admire your patience, how do you do it? People keep misunderstanding or even missing your points completely, but you simply start again and have another go at it...