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Discussion Starter #1
Hi guys,

I recently bought a laptop with a i7 4700MQ. According to the specs, it has a turbo boost to 3.2 ghz on all 4 cores.
However, when I'm encoding a video in Premiere CS6 and my CPU goes to 100%, CPU-Z shows that the CPU is operating at barely 3.0 Ghz. The multiplier is at 30x.

However, when I'm doing a playback in Premiere, the muliplier sometimes goes up to 33x or 34x and reaching the promised speed at 1 or 2 cores.

But when using 4 cores in an encode, it doesn't go to 32x / 3.2 Ghz as it should.

It makes no difference which power plan I use in Windows and the Bios gives me no information or options for the CPU. Maybe the manufacturer disabled that.

Lastly, and not unimportantly, there is no problem with the temperatures IMO. It does go up to about 82 C under full load after a while, but I see no signs of throttling. The multiplier maxes out at 30x even when I just hit the encode button and the temps are nowhere near 80 C yet.

So what's going on here? A faulty CPU? Or something I should change? Any thoughts?

Thanks guys, appreciate any input.

Bonus question:
Last week during encoding, my CPU did not get hotter than 63 C. Today in another room, but all same settings, it went up to 83 C... Both times the laptop was plugged in. The only difference is the room temperature, but that might only be 5 C warmer here.
Why could my temps be higher now? And is 83 C something to worry about?
 

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The 4700MQ has a long term TDP limit of 47 Watts and Intel recommends that laptop manufacturers set the short term limit 25% higher than this to 58.75W (1.25 X 47W).

http://ark.intel.com/products/75117/Intel-Core-i7-4700MQ-Processor-6M-Cache-up-to-3_40-GHz?q=4700mq

Long term, these CPUs will reduce the amount of Turbo Boost (throttle) to keep power consumption just under the 47W limit.

If you use offset voltage, this will reduce power consumption so the CPU can run a little faster before hitting the TDP limit.

These CPUs also support +2 bins of overclocking as long as you are running software that doesn't fully stress the CPU and you stay under the TDP limit.

QhbV0qb.png
 

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Discussion Starter #3
Quote:
Originally Posted by unclewebb View Post

The 4700MQ has a long term TDP limit of 47 Watts and Intel recommends that laptop manufacturers set the short term limit 25% higher than this to 58.75W (1.25 X 47W).

http://ark.intel.com/products/75117/Intel-Core-i7-4700MQ-Processor-6M-Cache-up-to-3_40-GHz?q=4700mq

Long term, these CPUs will reduce the amount of Turbo Boost (throttle) to keep power consumption just under the 47W limit.

If you use offset voltage, this will reduce power consumption so the CPU can run a little faster before hitting the TDP limit.

These CPUs also support +2 bins of overclocking as long as you are running software that doesn't fully stress the CPU and you stay under the TDP limit.

QhbV0qb.png
Thanks for your reply. I'm not really planning to overclock this CPU, I just want to know if everything is 'normal'.

What exactly do you mean with 'long term?'
That the CPU automaticly goes back to 47w and thus 2,99 ghz when doing an intensive task for more than a few seconds? So that it is normal what is going on?

Thanks again.
 

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3.2GHz isn't guaranteed on all four cores, only "possible". The part needs to be within TDP limits to reach max turbo and it's quite possible that transcoding exceeds this.

It's not the laptop manufacturer's limit, it's Intel's.
 

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Discussion Starter #5
Quote:
Originally Posted by Blameless View Post

3.2GHz isn't guaranteed on all four cores, only "possible". The part needs to be within TDP limits to reach max turbo and it's quite possible that transcoding exceeds this.

It's not the laptop manufacturer's limit, it's Intel's.
Thanks.

So, this is normal and every i7 4700mq which is not modified or overclocked will run at 2.99 ghz when doing encoding or a stress test for longer than a few seconds?
I think I get what you mean, but if the cpu does not get hotter than 75-80 degrees while tj_max is 100 degrees, why is it already limited?
 

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Quote:
Originally Posted by unclewebb View Post

Long term, these CPUs will reduce the amount of Turbo Boost (throttle) to keep power consumption just under the 47W limit.
This guy is right, in your scenario the CPU isnt throttled by the temprature, but by its power draw.
its only allowed to go over the set power limit by a short time.
 

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It sounds like your 4700MQ is running exactly as Intel designed it to run. All Intel CPUs can slow down and throttle if they get too hot but Intel's Core i CPUs like your 4700MQ can also be throttled based on power consumption. These CPUs have 2 different power limits. For a short period of time, the CPU is allowed to run at a higher power limit. The time limit that Intel recommends and most laptops use is 28 seconds. If you are doing a very intense task then the amount of time that you are allowed to run at the higher power limit will be reduced. Once this time limit is used up, the CPU automatically slows down (throttles) just enough to reduce power consumption back to the TDP limit. For a 4700MQ, that limit is 47 Watts. That is your long term limit. Your CPU should be able to run long term at 47W with no further throttling.

Some applications work the CPU harder than other applications. The harder an application tries to work the CPU, the slower the CPU will run in order to stay just under its TDP limit. Intel includes some special instructions in their CPUs called AVX and the new 4th Gen Haswell CPUs use AVX 2 instructions. In a laptop, these instructions consume so much power that if software uses these instructions extensively, a laptop CPU is going to really slow down and will not be able to run anywhere close to its maximum theoretical speed. When all 4 cores are fully loaded, the 32 multiplier is the maximum possible multiplier but it is not guaranteed. Most consumers do not realize this.

Anyway, here's an example using the latest version of Prime95. Version 28.1 uses the AVX 2 instructions and really gives a CPU a thorough work out. When I first start running this program, the CPU is allowed to run at about 56.6 Watts. If there were no power limit restrictions, this program could probably draw 80 or 90 Watts. In a poorly cooled laptop, the CPU would almost instantly reach the thermal throttling temperature and it would slow down based on temperature.

Prime95 - 56.6 Watts
http://oi62.tinypic.com/21no02c.jpg

Once the time limit is up, power consumption must decrease to 47W so the CPU automatically slows down to reduce power consumption.

Prime95 - 47.0 Watts
http://oi60.tinypic.com/2jbuzoh.jpg

The desktop K series CPUs use power limits that are fully unlocked. With a locked desktop or mobile CPU, you are much more limited.

Edit - Applications that do not use the new instructions can fully load the CPU and maintain a 34 overclocked multiplier without triggering the 47W TDP Throttle to kick in.

http://oi57.tinypic.com/20f6cmd.jpg
 

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Discussion Starter #8
Thanks unclewebb, clear explanation. I guess my CPU is working fine as is then. Good to hear!
 

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When encoding, if you want your CPU to use the full 32 multiplier, you need to reduce power consumption to stay under the 47W limit. With a 4700MQ, you do not need an option in the bios to access voltage adjustment. You can do this with software. A negative offset of -75 mV should be enough to get the full 32 multiplier when encoding.
 

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On the 4700MQ, a Windows Minimum and Maximum processor state setting of 99% or less will completely disable Intel Turbo Boost and leave this CPU running at the default 24 multiplier.

http://i.imgur.com/ovKP51q.png

That is not the problem that Stab has. When fully loaded, his 4700MQ is trying to exceed the 47W TDP limit. The CPU responds by reducing the amount of Turbo Boost to stay just under this limit. His CPU is working as Intel designed it to work.
 

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Iconoclast
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Quote:
Originally Posted by Stab View Post

So, this is normal and every i7 4700mq which is not modified or overclocked will run at 2.99 ghz when doing encoding or a stress test for longer than a few seconds?
It's normal, but every single CPU is different. It's completely possible for another i7 4700mq to reach the maximum 3.2GHz turbo bin doing the same task in the same conditions that causes yours to peak at 3GHz. Conversely, a worse sample may be limited even further.
Quote:
Originally Posted by Stab View Post

I think I get what you mean, but if the cpu does not get hotter than 75-80 degrees while tj_max is 100 degrees, why is it already limited?
You could easily have enough cooling to move ~47w of heat without getting your part over 80C, but the CPU is still capped at that ~47w.
 

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Quote:
Originally Posted by unclewebb View Post

When encoding, if you want your CPU to use the full 32 multiplier, you need to reduce power consumption to stay under the 47W limit. With a 4700MQ, you do not need an option in the bios to access voltage adjustment. You can do this with software. A negative offset of -75 mV should be enough to get the full 32 multiplier when encoding.
VERY interesting thread!

I had wondered the exact same thing that Stab did when using my i7 4700MQ-equipped laptop to render video . . .

Thanks, Unclewebb!

My related question is:
In Intel's Extreme Tuning Utility, is your "negative offset" what Intel calls "Dynamic CPU Voltage Offset'?

Thanks and . . .
Regards,
Robtl
 

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Quote:
Originally Posted by Robtl View Post

In Intel's Extreme Tuning Utility, is your "negative offset" what Intel calls "Dynamic CPU Voltage Offset'?
That is correct. Somewhere around -50 mV is a good place to start testing. If you got lucky and you have a really good 4700MQ, maybe you can run with -80 mV or -100 mV. It is best to test mobile CPUs for stability at idle, part load and full load. A -75 mV setting might be 100% stable in Prime95 but reducing the core voltage that much can cause problems when the CPU is mostly idle. If you start getting random BSODs when lightly loaded then that is a sign that you have decreased the core voltage too much. You will need to increase the core voltage until the light load BSODs go away.

You can also use XTU to reduce the Cache voltage a little. There are some more CPU voltages that can be adjusted but XTU might not have access to those voltages if your bios blocked them.

http://i.imgur.com/VM9dhgz.png
 

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Quote:
Originally Posted by unclewebb View Post

That is correct. Somewhere around -50 mV is a good place to start testing. If you got lucky and you have a really good 4700MQ, maybe you can run with -80 mV or -100 mV. It is best to test mobile CPUs for stability at idle, part load and full load. A -75 mV setting might be 100% stable in Prime95 but reducing the core voltage that much can cause problems when the CPU is mostly idle. If you start getting random BSODs when lightly loaded then that is a sign that you have decreased the core voltage too much. You will need to increase the core voltage until the light load BSODs go away.

You can also use XTU to reduce the Cache voltage a little. There are some more CPU voltages that can be adjusted but XTU might not have access to those voltages if your bios blocked them.

http://i.imgur.com/VM9dhgz.png
Mine can go up to -115mV so far, I'm pushing further for full Turbo speeds in Adobe Premiere editing and rendering. Right now it throttles down to 3.3 - 3.2 Ghz while editing and 3.4Ghz while rendering. Mine is a golden chip i guess.

How much further do you think I should go for the cache and iGPU?
 
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