520M stuck at 1.2Ghz

[Trackr]

I have an HP 6550b which has always run fine.

Today I noticed that it is stuck at 1.2Ghz (with a multiplier of 9x) and won't go up even with Prime 95. In fact, Prime 95 seems to not even work..

There are no options in the BIOS that I found that could help with this.

Any ideas?

 

[deaedius]

What are the CPU temperatures? It could have hit a threshold that is keeping the CPU at a low clock speed for protection.

 

[unclewebb]

If your CPU temperature is fine, download ThrottleStop and make sure BD PROCHOT is not checked.

When a sensor goes bad on your motherboard, if this is checked, it can send a signal to your CPU and force it to throttle down to the minimum speed. Turning off BD PROCHOT will disable these messages. After you do this, your CPU will still throttle if it ever gets too hot but it will ignore any outside messages to throttle. This is a common problem on many motherboards as they get older but most people do not keep a close eye on their MHz so they never notice.

 

[Methos]

I have no idea if HP does this, but Dell laptops check the charger on boot up, and if you use a 65 watt charger on a laptop that was shipped with a 90 watt charger, it'll whine at you before it boots. What it doesn't tell you is that it also throttles the CPU with the wrong charger. Disable speedstep in the BIOS and it will run full speed; but you lose the advantages of having speedstep on of course. Fuckin Dell.

 

[unclewebb]

Disable speedstep in the BIOS and it will run full speed;

On my Dell laptop with a Core 2 Duo, if I disable SpeedStep in the bios, it boots up and is locked at the lowest possible multiplier (6) and lowest possible speed so I would not recommend doing that.

BD PROCHOT stands for bi-directional processor hot. It allows other sensors on the motherboard or the power adapter to send a signal to the CPU. This tricks the CPU into thinking it is too hot. The CPU responds by slowing down to its lowest possible speed.

I am pretty sure that Dell uses this throttling method in many of their laptops. When you boot up and the bios detects a low power adapter or a non-Dell adapter, it sends a signal to the CPU using this method so the CPU throttles down and stays at its minimum speed. Disable the BD PROCHOT signal path and this will block any communication between the power adapter and the CPU. Problem solved.

Disabling BD PROCHOT will likely solve whatever is causing this HP laptop to throttle down. You might also need to use the ThrottleStop - Set Multiplier feature to get the CPU back up to its full rated speed. These problems are almost always solvable.

 

[Methos]

On my Dell laptop with a Core 2 Duo, if I disable SpeedStep in the bios, it boots up and is locked at the lowest possible multiplier (6) and lowest possible speed so I would not recommend doing that.

BD PROCHOT stands for bi-directional processor hot. It allows other sensors on the motherboard or the power adapter to send a signal to the CPU. This tricks the CPU into thinking it is too hot. The CPU responds by slowing down to its lowest possible speed.

I am pretty sure that Dell uses this throttling method in many of their laptops. When you boot up and the bios detects a low power adapter or a non-Dell adapter, it sends a signal to the CPU using this method so the CPU throttles down and stays at its minimum speed. Disable the BD PROCHOT signal path and this will block any communication between the power adapter and the CPU. Problem solved.

Disabling BD PROCHOT will likely solve whatever is causing this HP laptop to throttle down. You might also need to use the ThrottleStop - Set Multiplier feature to get the CPU back up to its full rated speed. These problems are almost always solvable.

Good info, thanks!