Author Topic: Why have CPU's stopped at ~1.8 GHz?  (Read 15448 times)

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Offline timb

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #75 on: June 01, 2017, 12:14:57 am »
Just remember that the declared clock speed of a processor is the speed of the external clock only.   They routinely divide that clock a lot before it reaches the ALU.   Different parts of the CPU operate at sometimes vastly different clock speeds internally.

That was true in the 70s and early 80s. It hasn't been true since around the 80486/68040 era, and certainly not since anything Pentium/PowerPC. Except for the dog called Pentium 4, where they bumped the MHz for marketing reasons, but it wasn't really real.

Indeed clocks these days are multiplied up for internal use.

Well, yes, the external 100 MHz or 133 MHz or whatever clock is multiplied by 30 or 35 or 40 or 45 to get the internal (and advertised) clock speed, and it's even adjusted dynamically for power consumption, temperature, or load reasons.

Even microcontrollers now have clock frequency multipliers. For example STM32F407ZGT6 can take an 8MHz crystal and generate a 168MHz clock out of it (8MHz / 8 * 336 / 2 = 168MHz.) this stands true for 8-bit cores too like ATtiny85 (8MHz * 8 / 4 = 16MHz) or PIC16F1455 (16MHz * 3 = 48MHz)

Some even have full PLLs with freely configurable clock trees! The PSoC 5LP can take a 2-40MHz crystal/external clock (or the 3-24MHz Internal Main Oscillator) and connect it to the internal Fractional-N PLL, which can generate any frequency up to 80MHz.

The Bus Clock and Master clocks also have (optional) individual dividers and can be derived from any of the above mentioned sources (PLL, Crystal, External Clock or IMO).

On top of that there are a number of freely configurable clock dividers to use as sources for the various analog and logic block functions (ADCs, DACs, CapTouch, Timers, PWM, SPI, I2C, Logic Gates, etc). This means virtually any peripheral can have its own unique clock that's in phase with the master clock.

There is also an onboard frequency doubler, designed to take a 24MHz clock and convert it to 48MHz for the USB controller.

It's the most flexible (and easiest to use) clocking system I've come across on a MCU.
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Offline Ampera

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #76 on: June 01, 2017, 02:01:46 am »
I'd bet it costs a lot more than you estimate to build those TI calculators. They may be overpriced but not to the degree you suggest.

You want an example of highway robbery just look at textbooks. They make trivial revisions consisting mostly of shuffling things around and call it a new edition which you then have to buy at exorbitant cost. Your expensive book is then almost worthless once a new edition comes out.

Textbooks are a rip too, that's why everybody's buying a cheaper EBook from some guy who probably scanned it all in.

And no, I definitely think they are that cheap to make. What's even in it? There is no rechargable battery, the screen is barely a screen, the keyboard is as cheap as you can get with actual buttons, and if the RasPi foundation can make a powerful ARM computer on a board for five bucks, I doubt that Ti is doing a Z80 board for any more than a dollar.
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Offline technix

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #77 on: June 01, 2017, 06:03:12 am »
I'd bet it costs a lot more than you estimate to build those TI calculators. They may be overpriced but not to the degree you suggest.

You want an example of highway robbery just look at textbooks. They make trivial revisions consisting mostly of shuffling things around and call it a new edition which you then have to buy at exorbitant cost. Your expensive book is then almost worthless once a new edition comes out.

Textbooks are a rip too, that's why everybody's buying a cheaper EBook from some guy who probably scanned it all in.

And no, I definitely think they are that cheap to make. What's even in it? There is no rechargable battery, the screen is barely a screen, the keyboard is as cheap as you can get with actual buttons, and if the RasPi foundation can make a powerful ARM computer on a board for five bucks, I doubt that Ti is doing a Z80 board for any more than a dollar.
The real cost might be in the validations TI made for those calculators. To get an calculator allowed in a test takes a lot of validation. The TI 84 Plus SE is authorized to be used in SAT and AP tests. SAT does not allow the TI-89 Platinum but AP still allows it. The Voyage 200 is more advanced a calculator than TI-89 Platinum (both calculators have the same hardware design) yet the V200 is cheaper (at least in local stores here.) The reason behind this was that TI-89 Platinum required more validation than Voyage 200.
 

Offline Ampera

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #78 on: June 01, 2017, 07:11:09 am »
The SAT allows all major HP calculators. It's the ACT that is strict, allowing only the HP48G as the most powerful HP Calculator. While I do have one, they are rare, and expensive.

HP is great for a class, but not for major testing, sadly. Some tests allow different calculators, and if your HP calculator is on that list, that's great. The 48G is often the lowest common denominator with testing. It's allowed almost everywhere the Ti-83/84 is.

The reason HP is banned everywhere is mostly down to the computer algebra system programmed into every modern HP calculator. The 48G does not have CAS (that being said it would be easy enough to implement) and is thus allowed on the ACT, provided you tape down the IR transceiver.

The HP Prime does have a testing mode, but it's not something most places want to bother with.

However, for those out of school, and those just in class, it's an amazing calculator. It's just too good for some testing.
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Offline JPortici

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #79 on: June 01, 2017, 07:52:19 am »
The PSoC 5LP

dsPICs can do that too.. and go higher in frequency >:D
PIC32 too

and now that i think about it, every cortex i've ever used
« Last Edit: June 01, 2017, 08:08:06 am by JPortici »
 

Offline brabus

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #80 on: June 01, 2017, 08:25:00 am »
I guess one of the reasons for the performance plateau is the lack of demand. Does anyone seriously need more desktop power? No. Today we just want the batteries in our smartphones to last longer.

Multi-GHz, Multi-Core SoC, thin as paper and barely lukewarm: this is the real modern days' miracle.
 

Offline Ampera

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #81 on: June 01, 2017, 08:35:03 am »
That's half the story.

For the longest time AMD has been choking on it's own bad decisions. It finally got 14nm fabs and is pulling into it's former glory with the Zen architecture.

Before Zen, Intel had no real reason to compete. With what? CPUs that were years behind their tech, and even then slower? AMD was kept alive by the fact they had a good graphics division, and in some cases had better price to performance than Intel.

Now that the former reigning champion is back in the ring, we will most likely see some more competition as Intel uses it's almost endless wealth to do something against the cry of Ryzen.

It's almost like a scuffle before the end of the world. As Moore's law comes to a close, with the need of a total rethinking of how we produce CPUs, nobody knows what the hell is going to happen. AMD is at the liberty of the fabs they contract, while Intel has all of their production in house. So if Intel comes out with some new way of going smaller, or expanding in some other form, AMD will have to wait for companies like Global Foundries to catch up, which was one of the main reasons for their multiple year slump.

My opinion is from a strange perspective. I still use legacy machines, and so do a lot of people. The microcomputer revolution has been the brightest and flashiest event in human history, and people are still catching up. I'm not sure what I am trying to say, but maybe we will forget about going faster altogether. Maybe we will come back to enjoy the technology we already have. It is my hope, anyways.

What I'm really trying to say is I'm bummed I missed out on Quantum Link and I want them to bring it back (JK)

It's going to be an interesting few decades for those who can make it. We don't know where the human race is gonna go, but there is one thing we all do know. This has happened before, and we have always gone past it. People have said we are going to stop and return to old ways, but we never have, and from an educated point of view, I think we're gonna end up continuing forward the same way we have been.
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Offline rdl

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #82 on: June 01, 2017, 03:31:21 pm »
I guess one of the reasons for the performance plateau is the lack of demand. Does anyone seriously need more desktop power? No. Today we just want the batteries in our smartphones to last longer.

Multi-GHz, Multi-Core SoC, thin as paper and barely lukewarm: this is the real modern days' miracle.

I sit at this desk and use this particular computer several hours a day. I built it in 2008 at a cost of almost $1000, but several parts have been downgraded since. It still does almost everything I need to do except run the more demanding games. I built a new computer for my lab bench almost 2 years ago. It is better than this machine in most ways, but cost less than $200 and uses less than 15 watts of power.
 

Offline james_s

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #83 on: June 01, 2017, 05:54:22 pm »
When I built my i7 desktop a couple years ago it was replacing a nearly 10 year old Pentium4 that still did about 90% of what I wanted to do with it. When I started playing with computers, one that was a year or two old was hopelessly obsolete, 10 years old would have been positively ancient. At this point I plan to keep using my i7 indefinitely, it's possible that something new and revolutionary will come out which will spur me to upgrade but lately it seems like software has peaked and has started to regress toward the lowest common denominator mobile platform. There is nothing compelling to upgrade to.
 

Offline David Hess

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #84 on: June 01, 2017, 07:37:46 pm »
The systems I regularly use are old enough that they are falling behind the supported software curve because Windows has deprecated so much hardware support.

I would accept higher power for higher performance if that was an option but Intel has been choosing smaller die area for lower cost.  This shows up in behavior like when you use the wider width vector extensions, the CPU clock speed is slowed down.  In some cases the loss of clock speed makes total performance lower than if the vector extension was not used.

Intel likes to pick benchmarks which take advantage of new processor features like instruction set extensions but I am interested in applications which do not take advantage of them.  Often this is because of Intel's market segmentation policies which discourage adoption of advanced features.
« Last Edit: June 01, 2017, 09:23:30 pm by David Hess »
 

Offline senso

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #85 on: June 01, 2017, 08:30:37 pm »
There is also the funny you need a kabylake+Win10+Edge to watch 4k Netflix...
For the 1.8Ghz thing, my laptop with a 4720 hits 3.8Ghz single threaded all day, and a depressing 3.6Ghz with all 4 cores pegged, using a bugged micro-code I could OC it, but there is no point in that..
The bottleneck is enough RAM and slow HDD's for years, a core2quad with an SSD and some 50$ GPU is more than enough for internet, and even basic CAD work, anything office related, etc.
 

Offline james_s

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #86 on: June 01, 2017, 09:12:09 pm »
One thing I've never quite figured out is YouTube. I used to be able to stream fullscreen with no issues on a 1.4GHz laptop from ~2004. Then it got so slow eventually that it was unusable so I upgraded to a newer laptop which again streamed full screen just fine, then that became unbearably slow. Now with a core i7 laptop I can again stream full screen but I've noticed CPU usage has increased lately to the point that the fan revs up when it never used to. All that and the video doesn't look any better than it did back on the old 1.4GHz laptop. It's just a steady and dramatic increase in CPU usage for no perceptible improvement.
 

Offline Carl_Smith

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #87 on: June 02, 2017, 01:38:40 am »
There is nothing compelling to upgrade to.

The one compelling upgrade everyone should consider is a solid state drive for your operating system.  The difference is amazing.  Programs load nearly instantly.  You'll be cursing your BIOS for taking 5 seconds to do it's thing because the OS only takes a few more seconds to load.  And the drives from good companies are very reliable now.

For most people - people who are not rendering video or worrying about frame rates in games - the apparent speed of your system is how quickly it reacts to your inputs, a lot of which are loading programs or files, and an SSD makes an amazing difference.


Offline Someone

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #88 on: June 02, 2017, 01:58:36 am »
One thing I've never quite figured out is YouTube. I used to be able to stream fullscreen with no issues on a 1.4GHz laptop from ~2004. Then it got so slow eventually that it was unusable so I upgraded to a newer laptop which again streamed full screen just fine, then that became unbearably slow. Now with a core i7 laptop I can again stream full screen but I've noticed CPU usage has increased lately to the point that the fan revs up when it never used to. All that and the video doesn't look any better than it did back on the old 1.4GHz laptop. It's just a steady and dramatic increase in CPU usage for no perceptible improvement.
Its the partly the underlying codecs in use:
https://blogs.gnome.org/rbultje/2015/09/28/vp9-encodingdecoding-performance-vs-hevch-264/
But also that the video quality keeps improving with higher and higher delivered bit rates, the minimum bitrate stream available goes up year on year. You could play full screen video stream on an intel MMX processor, but it was at a much lower quality than you would see today.
 

Offline Axl

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Re: Why have CPU's stopped at ~1.8 GHz?
« Reply #89 on: June 06, 2017, 06:42:09 pm »
For what it's worth:

Zilog ez80f91:
50 MHz
[seems like 4-6 stage] pipeline
Many instructions are single-cycle execution
Zero waitstate mem. access, using SDRAM
24-bit (data and address) bus
On-die EMAC coprocessor (100 Mb/s full duplex)
Etc.

 


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