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Arm unveils 7nm Cortex-A76 CPU

anandtech.com

31–40 of 67 posts

Re: Arm unveils 7nm Cortex-A76 CPU

#31
I do find these articles frustrating. They continue to rave about ARM (or Qualcomm) improvements, while casually mentioning that they're at least 2 years behind Apple. Being 2-3 years behind Apple should be front and centre of the article. It's a big deal! Unfortunately, as an Android user, I don't have a choice, and I suspect my next phone will have an SD845.

You didn't see that kind of leniency when AMD was releasing slow/inefficient CPUs pre Zen.

Re: Arm unveils 7nm Cortex-A76 CPU

#32
post #26

Earlier quoted context omitted.

the problem is that many low-end and middle-end android tablets are based on Cortex A53 which is a slow in-order CPU (but very power efficient).... The Flash storage performance is also very important for user experience and is often left behind in reviews

And what's often an even bigger deal is many of the low-to-mid end devices have very, very little cache (some have no L2 cache, even!).

Wait, what? I'm trying to think of an application SoC from the past 8 years that doesn't have an L2 cache.

Re: Arm unveils 7nm Cortex-A76 CPU

#33
I'm not a hardware knowledgable guy, but would love to read/hear an intro about what chip design is all about (at a lay person's level I guess).

I understand that ARM sells core designs, and that each company assembles them / designs them in the way suits their performance needs, and then gets them manufactured?

But what does that really mean? What is the "user" doing? Are they arranging them like kids' Lego blocks on a die surface? Dragging and dropping blocks of code? Are they tweaking the voltage settings? Are they combining them in ways that do sequential operations special to them? What's the added step here? Like, why doesn't ARM just create the chips that the end OEMs want?

Is it like cooking or chemistry? What's the closest analogy? I would love to get a more intuitive feel about what chip design is all about.

Thanks!

Re: Arm unveils 7nm Cortex-A76 CPU

#34
post #31

I do find these articles frustrating. They continue to rave about ARM (or Qualcomm) improvements, while casually mentioning that they're at least 2 years behind Apple. Being 2-3 years behind Apple should be front and centre of the article. It's a big deal! Unfortunately, as an Android user, I don't have a choice, and I suspect my next phone will have an SD845. You didn't see that kind of leniency when AMD was releasi…

I think you're expecting it to be a general purpose mobile CPU comparison, when it's not. It's a very specific look at the next generation of ARM processors. Similar to a look at the next generation of Intel processors or the next generation of AMD processors, it makes sense to compare and contrast specifically it to what came before in the same line. That said, they do include A10 and A11 processors in the benchmarks, so you can see how it is projected to perform in comparison with current processor lines.

Additionally, there's far more to compare that raw performance, especially when looking at these types of CPUs. Actual size (others here have mentioned Apple's processors are quite large due to cache), power draw at idle/peak, etc are very important for mobile CPUs.

In the end, it's not a buying guide, it's an info-dump about a new product.

Re: Arm unveils 7nm Cortex-A76 CPU

#35

Earlier quoted context omitted.

And what's often an even bigger deal is many of the low-to-mid end devices have very, very little cache (some have no L2 cache, even!).

Wait, what? I'm trying to think of an application SoC from the past 8 years that doesn't have an L2 cache.

I'm struggling to find the one I was thinking of, maybe I'm just imagining it. Most things I can find are 256kB/core, which is the same as most Intel chips (though the A11 is over 1MB/core!).

Re: Arm unveils 7nm Cortex-A76 CPU

#36
post #31

I do find these articles frustrating. They continue to rave about ARM (or Qualcomm) improvements, while casually mentioning that they're at least 2 years behind Apple. Being 2-3 years behind Apple should be front and centre of the article. It's a big deal! Unfortunately, as an Android user, I don't have a choice, and I suspect my next phone will have an SD845. You didn't see that kind of leniency when AMD was releasi…

I think it's because the ecosystems are quite different. In x86 processors you can swap them in isolation and keep the same connectivity standards, the same types of RAM, the same operating systems and programs. In phones you can't just buy an Apple processor and drop it in, you have to "sign up" for a whole ecosystem of particular devices, a single OS that runs on those devices, a single software store that serves that OS, a particular connector, etc.. A direct CPU-to-CPU comparison doesn't hold as much weight when you can't actually act upon it without changing a whole host of other stuff you might be perfectly happy with.

Re: Arm unveils 7nm Cortex-A76 CPU

#37
post #34
post #31

I do find these articles frustrating. They continue to rave about ARM (or Qualcomm) improvements, while casually mentioning that they're at least 2 years behind Apple. Being 2-3 years behind Apple should be front and centre of the article. It's a big deal! Unfortunately, as an Android user, I don't have a choice, and I suspect my next phone will have an SD845. You didn't see that kind of leniency when AMD was releasi…

I think you're expecting it to be a general purpose mobile CPU comparison, when it's not. It's a very specific look at the next generation of ARM processors. Similar to a look at the next generation of Intel processors or the next generation of AMD processors, it makes sense to compare and contrast specifically it to what came before in the same line. That said, they do include A10 and A11 processors in the benchmark…

The end result is that people who prefer Android devices are still stuck paying iPhone money for a phone that has much, much lower single threaded performance.

Re: Arm unveils 7nm Cortex-A76 CPU

#38

Earlier quoted context omitted.

Wait, what? I'm trying to think of an application SoC from the past 8 years that doesn't have an L2 cache.

I'm struggling to find the one I was thinking of, maybe I'm just imagining it. Most things I can find are 256kB/core, which is the same as most Intel chips (though the A11 is over 1MB/core!).

Yeah, you borderline need an L2 for any multicore systems. L2's main job on most designs is coherency and reducing the explosion of bandwidth needs from the cores all vying for the main memory bus.

Re: Arm unveils 7nm Cortex-A76 CPU

#39

I'm not a hardware knowledgable guy, but would love to read/hear an intro about what chip design is all about (at a lay person's level I guess). I understand that ARM sells core designs, and that each company assembles them / designs them in the way suits their performance needs, and then gets them manufactured? But what does that really mean? What is the "user" doing? Are they arranging them like kids' Lego blocks o…

ARM designs processors, but just the processor. I̶t̶ ̶d̶o̶e̶s̶n̶'̶t̶ ̶a̶d̶d̶ ̶p̶e̶r̶i̶p̶h̶e̶r̶a̶l̶s̶ ̶t̶o̶ ̶i̶t̶;̶ (also wrong here, apparently they make plenty of peripherals)., that's the job of the vendor who uses the processor and integrates it with RAM, Flash, protocol hardware (SPI, I2C, Serial, USB, etc), Timers, and all the other goodies that make a microcontroller easier to use because you dont need fifteen other chips to get it doing what you want it to do.Imagine needing to buy a separate chip so you can speak I2C, another to speak SPI, another to have a counter running and interrupt the processor every X seconds, another to store program memory, another to convert analog signal to digital; it would be unwieldly, so these vendors take the processor and attach these peripherals and say "the processor can use this peripheral by writing 0xAB to its register located at 0x12345678.

So you can think of ARM as designing the engine, and the vendors as taking the engine design then adding the rest of the cars features (chassis, electronics, navigation, etc) around it, then building and selling it.

"Why don't the vendors just design their own processor to go with their own peripherals?" you might ask. Well designing a processor is MUCH harder to do well than any of the individual peripherals. There is a lot more going on with a processor and it's at least an order of magnitude more complex than any of the peripherals that go with it. But that doesn't mean it's not done; Atmel designed the AVR architecture and this is the processor architecture that dominates the Arduino world. Atmel sells microcontrollers with their AVR architecture processor and their own peripheral designs as well. But AVR is mostly 8-bit and they can't compete with the performance of ARMs 32-bit designs; which is why you see ARM is most embedded applications.

The design for the processor is made in a program that lets you "lay out" the hardware at the transistor level and specify processes for it (like a lithographic mask) but ARM never carries out these processes, these must be taken care of by a fabrication facility. Oftentimes these vendors don't even have fabs themselves, they just design the rest of the "car" and then have it fab'ed by a third party.

~A̶R̶M̶ ̶d̶o̶e̶s̶n̶'̶t̶ ̶w̶a̶n̶t̶ ̶t̶o̶ ̶d̶e̶s̶i̶g̶n̶ ̶p̶e̶r̶i̶p̶h̶e̶r̶a̶l̶s̶ ̶a̶n̶d̶ ̶f̶a̶b̶r̶i̶c̶a̶t̶e̶ ̶c̶h̶i̶p̶s̶ ̶(̶i̶t̶ ̶d̶o̶e̶s̶n̶'̶t̶ ̶e̶v̶e̶n̶ ̶h̶a̶v̶e̶ ̶a̶ ̶f̶a̶b̶,̶ ̶n̶o̶r̶ ̶d̶o̶e̶s̶ ̶i̶t̶ ̶w̶a̶n̶t̶ ̶t̶o̶ ̶d̶e̶a̶l̶ ̶w̶i̶t̶h̶ ̶3̶r̶d̶ ̶p̶a̶r̶t̶y̶ ̶f̶a̶b̶s̶)̶.̶~ (Looks like i'm totally wrong here, also why doesn't HN have strikethrough comments implemented?). They do what they do - design processors - and they do it really well, so well in fact that vendors are more than willing to pay for a license to use their processors in their own chips so that the vendor doesn't have to deal with the headache of making a really good processor.

Re: Arm unveils 7nm Cortex-A76 CPU

#40
post #37
post #34

Earlier quoted context omitted.

I think you're expecting it to be a general purpose mobile CPU comparison, when it's not. It's a very specific look at the next generation of ARM processors. Similar to a look at the next generation of Intel processors or the next generation of AMD processors, it makes sense to compare and contrast specifically it to what came before in the same line. That said, they do include A10 and A11 processors in the benchmark…

The end result is that people who prefer Android devices are still stuck paying iPhone money for a phone that has much, much lower single threaded performance.

At what point does any user stop to complain about their single threaded performance on their handheld device? Quite literally the two devices are incomparable as Apple is a service with proprietary devices. Their selling point is all _their_ software will run similarly anywhere on any device. Android is free of that cycle, thankfully.
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