i7-3630qm throttles to 1200 Mhz at less then 70°C if Turbo Boost is enabled

I have an Asus laptop with hm76 Ivy Bridge chipset with Intel i7-3630qm, the CPU is 2.4Ghz and can Boost up to 3.4Ghz.

What happens is the CPU throttles to x12 (1.2Ghz) when Turbo Boost is enabled, this at less than 70°C, the TCC activation temperature should be 95°C!

The bios has the latest microcode patch v. 1C from Intel and before had the v. 15.

I made a test with cinebench and monitored the behavior of the cpu with Intel Power Gadget, ThrottleStop and SpeedFan, I made a video.

As you can see what happens is if I disable Turbo Boost with ThrottleStop the multiplier goes straight to x24 and the temperature goes up yet no PROCHOT signal is sent.

If I disable BD BROCHOT the temperature goes up but never arrives to 95° .. it arrives to 80° / 81° C.

So what is going on with this CPU??





And here another test: GeekBench with prochot disabled:





and here enabled:

 

whatever crap you installed must be interfering with turboboost in the background.
I bet a clean installed system, or one without cpu-control apps installed would function normally

 

This is a clean install for testing purpose, there is not any crap nor any third party power management software.
Fan and heatsink are squeaky clean too.

 

BD PROCHOT stands for bi-directional processor hot. This is a signal path to your CPU. There is a sensor on your motherboard that is using this signal path to throttle your CPU down to the 12 multiplier. This sensor might be temperature related or power related. You would have to find an engineer at Asus to explain this one but that is never going to happen so you have 3 choices.

1) Do not run ThrottleStop so your laptop can run like crap as the CPU randomly and continuously throttles. I would not vote for that option.

2) Use ThrottleStop to disable Intel Turbo Boost. Your CPU will run slower, at far less than its Intel rated speed but this might be enough to prevent it from triggering any further throttling. I wouldn't vote for this option either.

3) How about use ThrottleStop to disable the BD PROCHOT signal path. This blocks these external throttling signals from getting to your CPU so it can run at its full rated speed. The BD PROCHOT signal is completely different than the PROCHOT signal. Same sort of name but 2 different signals. If you choose to disable BD PROCHOT, the PROCHOT signal will still go active if your CPU ever reaches the thermal throttling temperature which is not until 105°C for your CPU. This means with BD PROCHOT disabled, your CPU will still be able to throttle if it ever gets too hot.

Asus and many other manufacturers have these sort of issues. I am assuming your warranty is over so replacing the motherboard to try to solve this problem is not worth it. A new motherboard will either have this problem right away or it will develop this problem soon after. The best and cheapest solution is to just run ThrottleStop and problem solved. Reinstalling Windows is not going to fix a sensor that has gone bad.

Edit - ThrottleStop is showing the correct 105°C TCC activation temperature for your CPU model.

http://ark.intel.com/products/71459/Intel-Core-i7-3630QM-Processor-6M-Cache-up-to-3_40-GHz

 

Thanks for the reply, however since I am running osx as main os I can't use throttle stop. Tomorrow I will try to fit an i5-3230m in the pc and see what happens. Besides if the problem is related to a failing sensor how comes the temperature is reported correctly? I mean, who is reporting this temps to the OS ? the CPU ? The MB?

 

The temperature sensors on the individual CPU cores are fine. It is usually a separate temperature sensor on your motherboard or on your voltage regulator. This signal might be triggered by power consumption so if you switch from a quad core CPU to a dual core i5-3230M, this problem might go away.

I know on some Dell laptops, the power brick itself can send a signal via the BD PROCHOT signal path which will force the CPU to throttle to the minimum multiplier. Do a Google search for "BD PROCHOT" with the quotes and you will start to see how many laptops have this problem.

You will have to do some testing with OSX. If the operating system leaves that single bit within the CPU turned off, your computer will run properly. If the BD PROCHOT bit is set, you will have the problems that you are having. There is nothing wrong with your i7-3630QM. BD PROCHOT means it is a signal external to the CPU that is causing the problem. ThrottleStop is the only Windows app that I know of that lets you disable BD PROCHOT. This is not well documented so you are not likely to find a similar app for OSX.

 

So I put the i5-3230M in the Asus and it doesn't throttle at all. I also put the i7-3630qm that was in the Asus in an Acer p253m and it also works without throttling.

 

A dual core consumes less power compared to a quad so the trigger might be power consumption. Same thing when you disable Turbo Boost. This reduces power consumption so it avoids triggering throttling. It is next to impossible to find motherboard schematics which clearly lays out exactly what sensors are tied into the BD PROCHOT line going to the CPU. At the end of the day, it doesn't really matter what it is, as long as you have found a way to control it. Disable BD PROCHOT and problem solved. No need to disable Turbo Boost if BD PROCHOT is disabled when running your i7.

Edit: BTW, I liked the useless answer that the Intel rep posted on their forum to your question. Intel and Dell both kicked me off of their forums because they do not like it when the truth gets out.

Edit #2: I am pretty sure that BD PROCHOT is enabled when running OSX.

 

I think maybe it's power consumption as you suggested. This laptop initially had an i3-2370M (yes a Sandy Bridge CPU on Ivy Bridge PCH). That CPU has a max power consumption of 35W, the i7 has 45W... the i5-3230M that I fitted now also has 35W. I see there are two i7 models for this PCH that have max power of 35W, the i7-3612M and the i7-3632QM. I wonder if fitting one of these would trigger throttling, my guess is not.
About the bios, it doesn't have the BD PROCHOT enable/disable feature but now I am wondering if the DSDT thermal zone can be patched to prevent taking action when the HOT signal is received. I have to read ACPI documents.
What do you think? Did you ever looked into DSDTs?
As you may know when running OSX we have to inject a patched one so that the bios is overridden.

 

I am not familiar with OSX so I cannot help you with that.

In the ThrottleStop TPL window, depending on if your bios left the power register unlocked, you might be able to adjust this down to 35 Watts to simulate a lower power CPU when testing with your 45 Watt i7. Sometimes the Package Power Limit will be locked but the Power Limit for the individual cores, PP0, will be left unlocked. On my 4700MQ, I can drop the power limits low enough to simulate having a low power U CPU. Handy for testing purposes.

 

Hi Chriz74,

I actually suffered the exact same problem with Samsung Chronos 7 Series NP780-Z5E with i7-3635QM 2.4Ghz with 3.4Ghz max single core boost; and Radeon HD8770M 1GB videocard after installing Windows 10 and running various updates over the last month.

I reset the BIOS to standard defaults (Press F2 right before boot), disabled the Radeon GPU (as I thought it may have been working and sharing PSU/battery power with the CPU), took apart the laptop and cleaned the dust (while at it, I replaced the horribly slow 1TB Samsung SpinPoint M8 5400rpm mechanical drive with a 500GB Samsung 850 EVO -- this made a world of a difference for me in terms of overall system snapiness -- BTW Samsung incorrectly lists Series 7 as SATAII but it supports the full SATAIII and the EVO gets 544MB/s reads and 512MB/sec reads/writes in CrystalDiskMark). I also reset all the Power Option profiles and played with Processor Power Management but nothing worked.

The answer lied in pressing Fn+F11 to manually boost/wake up the CPU Fans. I had to press it 5-10 times for it to finally work and now the CPU boosts to 3.2-3.3Ghz. After that I set the Battery Life Extender to 80%, set Samsung Power Optimized profile, and the CPU works properly. I was literally ready to go out and buy a new laptop as 1.2Ghz wasn't sufficient for my needs. It must have been a software glitch.

Hope this helps.