CPU stuck at 0.78GHz [VN7-591G]

Hi guys,

My VN7-591G often becomes stuck at 0.78Ghz and 8x multiplier - which makes it impossible to play games.

I have done extensive troubleshooting: Checked power management settings, updated drivers, rebooted in safe mode etc. No success.

I eventually found a workaround: If I shut down the computer and start it without my external monitor plugged in, the CPU stays at full speed! But only until I put the computer in sleep mode and wake it up later, then it throttles down to .78GHz after 1-2 minutes. This means that I must do a full power down and unplug hdmi cable each time I use the computer. Really annoying.

I can see that many others have similar problems in the forum, but no real solution or answers from Acer. Only option seems to be to install the ThrottleStop program - I don't think that is a good long-term solution.

Do you have any advice or should I return it and claim warranty? Bought the computer 6 months ago, same problem since day one...

I use Win10 and BIOS 1.15. CPU is i5-4210H.

Accepted answers

All comments

philetus

Have you tried unplugging the HDMI before putting it to sleep and plug it back in after it wakes up?

Fulgurator

Hi philetus,

Yes, following your suggestion keeps the CPU at full speed. However, I do not want to unplug/plug in a cable each time I want to use my computer.

Any other idea how to solve this? If it is a hardware malfuncion I guess the CPU/motherboard must be replaced, otherwise it should be able to be fixed through a BIOS update or similar. However, it seems to be a rather common problem. Is Acer technicians looking into this?

philetus

Have you tried shutting down completely, not restart?

Do you have the Laptop display off or do you have both displays?

Is it a monitor of a TV?

Seems lots of people have this problem. Most often used fix is use Throttle Stop to set the multiplier.

https://www.techpowerup.com/downloads/2288/throttlestop-6-00/

benton582

Okay, I'm gonna say something that might help, but you might have tried already.

Go to your "High Performace Power Plan"->Change Advanced Power Options->Processor Power Management->And set everything to 100%. If you are running above the resolution, that might be the problem, as higher resolutions need more computing. And Windows 10 is really glitchy right now as well.

If that does not work, it might be a Acer design flaw...

Fulgurator

Hi,

I checked power options and everything is at 100%.

My hope is that Acer will fix this either with a Bios update or with a graphic driver update. Or somehow related to buggy Windows 10.

It is a joke that Acer does not officially support newer drivers for the Intel graphics. I am blocked from installing latest drivers. And the ones on Acer website are really old.

Since I found my problem being related to HDMI output, I hope a driver or bios update would fix things.

How likely would you say that it is that this problem is strictly hardware related, i.e. malfunctioning motherboard?

philetus

I don't believe it's hardware related.

Put it to sleep and wake it so it throttles and check the Processor Power management in Power Options and see if anything changed.

uninstall Power Management, reboot and try it with the MS driver and see if it will wake up correctly. Reinstall the Acer driver and check again.

ePower

Acer

Power Management

7.00.8109

28.3 MB

2015/09/16

Download

jponte

Hello everyone,

I also have this problem and I'm going to explain why the CPU stucks at 0.78ghz.

Actually, if the CPU stucks at 0.78ghz is because... THE CPU FAN HAS STOP WORKING !

And when you use the app ThrottleStop to disable "BD PROCHOT" you just bypass the intel security and your CPU is overheating => it is not a viable solution.

2 solutions to see if your fan is off:

- By feeling it with your hand while your running an app like prime95 (CPU intensive)

- By running the app "RW-everything" and see the Offset "07-90" "08-90" if it indicates "FF FF" then the CPU Fan is not working.

So the real question is :

WHY THE CPU FAN STOPS BY HIMSELF AT RANDOM TIME ? AND WHY WHEN YOU POWER OFF then ON With HDMI UNPLUG, THE FAN TURNS ON AGAIN ?

This issue is REALLY annoying...

Have a nice day !

Ace187

Hi,

I have the same problem with my Acer Aspire V17 Nitro VN7-791G-70M4. It is driving me crazy! It always gets stuck at 0.78 ghz. Is it possible that no one knows a solution to this problem? After some research on the internet, there are quite a lot of people having this problem and not only with Acer. I`ve read also that some Mac`s have this problem but only when running Windows 10 on them. So I am beginning to think that this is maybe a Windows problem. Please if somebody knows the fix, share it.

ven98

So your is CPU frequency is stuck at 0.78GHz, no matter what you do, right? Does it stay at this frequency all the time or occasionally from time to time? Also do your fans spin at max speed constatly without being able to reduce their speed in any way?

Ace187

Hi,

Yes. Sometimes it worked for a couple of days and then all of a sudden its back to the same problem. Also when i turn the notebook on it works normally at 3.20 ghz. Then i start a program which normally should work at 100% full speed. The fan starts up at full speed and after approximately 10 to 20 seconds the fan stops and at the same time the cpu drops to 0.78 ghz. But the cpu also drops to 0.78 ghz by itself after some time, without starting any program. You think the fan is broken? Some people that have the same problem said that after they changed the motherboard they fixed the problem, but the motherboard would cost as much as buying a new notebook so i hope its not this problem as my notebook is only 3 years old.

ven98

I would try to reset the battery. The battery reset hole is at the back of the laptop and after you press the switch inside leave the laptop 10minutes and then press the power button for 30 seconds. If you have removable battery just remove the battery for 10minutes. I would also update my bios if it is not to latest version.

Ace187

Hi,

I tried the battery reset but unfortunately it didn't work. I tried also reinstalling windows 10 it didn't help either. Also i tried installing all the drivers from intel and nvidia to be up to date but also no change. I tried starting in safe mode to check if it works there and it doesn't drop to 0.78 ghz. It stays constant at 2.50 ghz without the turbo boost to 3.5 ghz. Also the fans start up normally from time to time.

ven98

Then it probably is an issue with the BIOS. Make sure that you update the BIOS to latest version.

Ace187

Hi,

Thanks for taking the time and for the fast replies. I forgot to mention, i updated the bios from the acer website, version 1.14. Is this the new/right version or is there another version available?

ven98

If there isn't newer version in Acer's website then it is the latest. If this didn't fix the issue then it is some controller issue and Acer should be able to fix it by fixing the bios. I don't think it is any hardware issue because you say sometimes it works fine.

Ace187

Ok. Thanks for your time. I'll probably going to send it to acer then to see if they can fix it. I hope its not a hardware problem as it's just a few months since the warranty expired.

jponte

Hi,

Same problem, read my previous post.

The problem is the fan stopping so the intel security bdprochot is activating.
You can bypass the security with throttlestop but the gpu fan will have to cool the gpu and the cpu too.

Acer never made a fix because i think it is a hardware problem.

Cheers

Ace187

Hi,

Thanks for the reply. But why is the fan stopping? I observed that the cpu drops first to 0.78 ghz and then after 5 seconds the fan stops working. So it doesn't seem to be fan related in my opinion, i don't know. Is it safe to use this throttlestop though? I wouldn't like to fry my cpu and thats not a long term solution for me. Also I've read that someone had the same problem with a Mac when using Windows, when using OS X it performed fine. So whats the connection with Windows and this fault? Maybe an update or compatibility issue? There must be a fault somewhere and i hope that acer knows about this problem and works on solving it. It is pretty annoying when you spend over 1300 Dollars for a laptop and it has problems like this, especially a few months after my warranty expired.