Throttled so hard it's almost dead

[Steve Kerry]

My PC has been getting slower, and I was always going to get around to fixing the problem. Last week I reinstalled Windows 10, figured that would fix it. It didn't.

I have now consulted all manner of software, and decided I don't understand most of what it is telling me. What I have discovered is that my CPU appears to be limited to 15w which explains why the performance is so crap. Power setting is Performance, both Min and Max are at 100%. All other settings are on default. Cooling is more than adequate, and I'm running a 700w PSU.

CPU: i5-4690K @ 3.40GHz
Mobo: Gigabyte Z97X-OC
RAM: 32GB
CPU: GTX1060 6GB
OS: Windows 10 Pro 64-bit

I'm hoping someone can take a look at these Throttlestop screencaps and tell me how to get some power back in my CPU, thanks.

 

[boju]

What psu model is it?

How have you got the cpu power connected? If im looking at the correct board, you have 1x 4pin and 1x 8pin correct? Which one of those are connected?

The stand-alone 4pin is meant for extra power for overclocking when the 8pin is also connected but not necessary. The 8 pin is what should be used with either a 4pin or 8pin from the psu.

Im not sure if using the additional 4pin only on the motherboard, if that's what you're using, is correct or not.

 

[Steve Kerry]

My bad, I said it's a Z97x, it's actually a Z87x-oc. There is a 4-pin socket (ATX-12V) and an 8-pin socket next to it (ATX-12V_2x4), I have a 4-pin lead plugged into the right side of the 8-pin socket (which is what the manual says to do). I have spare outputs on the PSU (Nesteq 700), if one of those is suitable I can connect that to the 8-pin socket...?

 

[Steve Kerry]

This is my PSU...
http://www.overclock.co.uk/product/NesteQ-Asm-Xzero-700W-XZ-700-Heatpiped-Cooled-Semi-Fanless-PSU_45668.html

 

[boju]

Sorry i went down the street.

I had a look at your psu and it does come with an 8pin 12v EPS plug, try that instead.

Connectors
- 20+4 pin ATX connector 60 cm (approx)
- ATX12V 4-pin support
- EPS12V 8-pin support
- 2 PCI-E support (6+2 pin)
- 6 SATA connectors
- 6 Molex
- 2 floppy
- 1 x 5V and 1 x 12V (both can power 3 fans each) Fan connection cable

4pin atx cpu 12v plug should have been enough but perhaps not.

 

[Steve Kerry]

Thanks Boju, I'll try it tomorrow - it's 1am here and time for bed...

 

[unclewebb]

All you have to do to fix this problem is use ThrottleStop and disable BD PROCHOT. This is a signal path to your CPU and can trick your CPU into thinking that it is running too hot even when the temperatures are fine. The CPU responds by dropping the multiplier down to 8 so your CPU is left running at 798 MHz regardless of load. Not good. Disable BD PROCHOT and your CPU will ignore this signal and be able to run at full speed.

Is this dangerous? No. If your CPU ever gets too hot, it will still throttle and slow down just like it is designed to do. Disabling BD PROCHOT only blocks throttling signals outside of your CPU. This is almost always triggered by a bad sensor on your motherboard.

 

[Steve Kerry]

Thanks unclewebb, I had figured (by playing what-does-this-button-do?) that BD PROCHOT was somehow involved, but I was a bit cautious about turning it off altogether.

When I call up Limit Reasons, I get the box with yellow tags show below.

If BD PROCHOT is ticked, I get the box with red tags (and as you say, multiplier drops to 8). I have no idea what the red signifies. C0% also rises, not sure if that is connected?

 

[unclewebb]

The yellow boxes in ThrottleStop indicate records of previous throttling events and why. The three yellow BD PROCHOT boxes show that this method of CPU throttling has been used on your CPU since you booted up. Boxes in red mean that this method of CPU throttling is currently active. Your CPU is throttling to 800 MHz because the CPU is receiving a signal on its BD PROCHOT line.

BD PROCHOT stands for bi-directional processor hot. A sensor, likely on your motherboard, has gone bad and it is sending a signal to your CPU which forces it to run as slow as possible because the CPU believes that it is too hot. Your CPU temperatures are fine but your CPU has to obey this request.

When you clear the BD PROCHOT box in ThrottleStop, this is the equivalent of disconnecting the BD PROCHOT signal line that goes to your CPU. As soon as you do this, your CPU will start running at its full rated speed. No more throttling. That is exactly what your pictures show. The 36 multiplier is the normal multiplier that a 4670K uses when 4 cores are active or when you have disabled your C States in the bios.

The C0 state is the state that a CPU is in when it is actively working on a task. When your computer is idle, it will not have to spend much time in the C0 state. It will mostly just be sitting their in C1, waiting for something to do. A fast CPU can process all of the various Windows background tasks a lot quicker than a CPU that is stuck at 800 MHz. When your CPU is running fast, it does not need to spend nearly as much time in the C0 state working. That is why the C0% reported in ThrottleStop decreases. When your CPU is in slow and sluggish mode, running at 800 MHz, it will have to spend far more time in the C0 state processing background tasks. The difference in C0% you are seeing confirms that the CPU at 3600 MHz is running 4.5 times faster compared to 800 MHz. 6.6% / 4.5 = 1.5% Make sense?

This is an obscure but common problem in laptops. The only way to repair this problem is to replace the motherboard. It is far cheaper and easier to just use ThrottleStop and keep the BD PROCHOT signal path permanently disabled.

As mentioned before, disabling BD PROCHOT will not interfere with your CPU throttling if it needs to if it ever gets too hot. The PROCHOT signal (processor hot) is completely different than the BD PROCHOT signal. PROCHOT is internal to the processor. BD PROCHOT is for external sensors.