T7700 wimps out, underclocks itself a lot

Okay, my problem is such that my laptop works fine and everything until I do the slightest processor intensive task (video render, Prime95, whatever). In fact, until I discovered RM Clock, I thought "100% CPU" in Task Manager meant that it was running at 2.4 GHz on both cores.

Well, I've come to find out that the reason for the random slow-downs I experience (HD playback is smooth, then it grinds to a halt) is that about a minute after running at the full 2.4 GHz, the processor throttles itself down to about 600 MHz, making my laptop about as powerful as a new cellphone. I've tried forcing it to stay at 2.4 GHz by selecting only the 12x multiplier in RM Clock, but it throttles itself down anyway. I assume this is because the temperature gets too high? But shouldn't a laptop's fans be designed to handle it's maximum performance for more than a minute or so?

The only thing that I can think of causing the problem is that I had to replace the motherboard in the laptop about half a year ago (it's a Dell D630) because the original one had one of those faulty nVidia GPUs. And I have the latest BIOS, so I am wondering if either of these is the cause (Dell purposely erring on the cautious side so as to not overheat the GPU).

And no, there's no dust in the vents.

Anyone have a similar problem or have solution advice?

Thanks a lot!

I've attached a screenshot of RM Clock illustrating the problem. It's been running Prime95 for a few minutes.

 

Maybe you didn't attach the heatsink properly

 

T7700 Tjunction is 100c. In the attached picture his temperature is only ~75c. What I'm trying to say is if it was a heat problem it is more likely that his CPU will slow down just untill its temperature dops down to about 90-95c not 75c.

I spoted few inconstancies on the attached:
1- CPU clock is shown 2393Mhz (~2.4Ghz) and the throttle is shown at 689Mhz
2- Below that the multiplier is shown to 12x and the VID 1.325v.
x12 is too high for 600+Mhz. Same for the Vcore.

This two points confirm:
1- The CPU is running at 2.4Ghz and that the OP has probably selected/checked the throttling options in the "Profiles" tab (under one of the profiles). To the OP please unselect "Use throttling (OCDM)".

2- That the OP has not undervolted his CPU at all. Again to the OP use this tutorial to set RMclock properly (ViD at x12 is too high at 1.325v. it sould be down to about 1 to 1.1v)
http://forum.notebookreview.com/showthread.php?t=235824

 

Thanks for the reply! I just checked those things naton, and mine is set for using P-state transitions (throttling is unchecked). Only index 7 (12x) is selected like I thought.

And you're right. In that screenshot I did not undervolt. I have undervolted it as well though, and the time that the CPU goes without throttling lengthens, but it still reaches that point in a few minutes and stays there for a long time.

 

Why are selecting index 7 only? you should select all of them, and undervolt all of them in both.Also you should select all the multipliers in the main "profiles" tab and in the "performance on demand" tab. Then make sure to select as your default "performance on demand" in the "profiles" tab (for "current" and "startup").

What I don't get is why do you want your CPU to run at 2.4Ghz all the time. A laptop CPU has the capacity to lower it speed when it is not needed and to increase it when it is needed. This technology is called Speedstep by Intel, and PowerNow by AMD.

 

The reason I was selecting 7 only was because that was the 12x multiplier which would put the clockspeed at 2.4 GHz. I thought that when it was throttling down to a lower speed it was because the other multipliers were checked (this wasn't the case).

And I don't need my CPU running at 2.4 GHz all the time. The point though is that when I do need it (like in a video render or using CoreAVC), it underclocks itself to 600 MHz and stays there for about 15 minutes before coming back up to 2.4 GHz for a minute and a half then going back down.

In fact, I think I should do some more investigating. I was running Prime95 on battery power (as opposed to in the docking station on AC power like I normally do), and it didn't exhibit the problem I described. Instead it stayed right at 2.4 GHz for about 15 minutes, the CPU temperature shot up to 96 degrees C and then it shut off (probably to avoid overheating). This is indeed quirky.

 

Okay so there's no dust in vent, how about thermal paste?
what and how are you using ? and does the fan work like normal or not?

I'd redo the cpu, thermal paste and heatsink just to be safe.
15 minutes and above 90C is hot alright.

 

Yeah I'm starting to wonder about thermal paste.. See, when I replaced the motherboard with the new GPU and put the original CPU into it, there was this sticky pad (looked like wet clay) that said to peel off and press onto the CPU (no thermal paste like the kind I've spread onto desktop CPUs). I assumed the pad was some sort of heat transferring paste-- you think I should take the laptop apart and put some thermal paste between these two?

 

Big Yes. (Edit: remove it and put your thermal paste of choice)
I wouldn't put that kind of thermal material for cpu (I think it's more like thermal pad / cheap cpu thermal thing)

even with Tuniq TX-2 and no undervolt my T7700 only reached 75C max,
and got better after undervolt (67 max)

edit: how about the fan? is it working normally?

 

Don't use thermal past and the sticky pad at the same time. For the CPU it is either the pad or the past not both at the same time. I'm like crayonyes I would recommand using a good quality thermal past such as arctic silver 5.

For the GPU it all depends on what you already have. If you have the same clay material as the one used with the CPU, then replace it with thermal past. If you have a thermal pad (usualy they are blue) then just reuse it without adding any thermal past.

Question:
Are you sure the PAD was not meant for your GPU?

 

Check thermal paste i would, if nothing else seems to solve the problem. Despite software telling you that the thermal sensor is reading 75C, there could be specific spots on the processor that reach in excess of 90-100, it's not totally accurate, perhaps you just got a laptop with spotty thermal paste application. Too much thermal paste will only raise the average CPU temp at load, i use the dab and spread with heatsink method, dab it on the CPU which should be mirror clean, and then apply the heatsink, but move the heatsink on the CPU around a bit to spread the thermal paste and get rid of air bubbles. My T61p had thermal paste on both the CPU and GPU when it was stock, i've replaced it since it dried out a little, the only pad i have is the one that's on the southbridge, attached to the heatsink.

 

100c is still not enought to shut an intel laptop OFF. The critical temperature for an intel Core 2 Duo is 120 to 125c.

Could your CPU throttling because your laptop is not supplied with enough power? I'm thinking of a faulty power supply.

 

Incorrect on both accounts man sorry, but the critical temp for all Core 2's is 105C, no higher, GPU's may get higher without damage but no, and 105C is when the OS should automatically shut down...

Also, the power brick is meant to supply enough power for peak load and then some, it's designed to have alot of room for error, if it was not supplying enough power the laptop would never reach 2.4GHz, never not even for a second since there physically would be too little power. The max TDP of most laptops is much under the power bricks that are supplied with them, and the max TDP situation is theoretical, meaning usually in most cases even though you may think you are operating under peak consumption, you deffinitely aren't.

 

YOU'RE WRONG. SORRY TO SAY THAT.

1- I'm too lazy to check the Core 2 Duo datasheet again, otherwise I would have told you in which document and which page(s) you can check the following information. The 105c is the CPU's Tjunction. At this temperature it will throttle down in an attempt to cool itself off. If this doesn't work and the temperature carry on increasing, the CPU will shut itself OFF but not before reaching 125c.

2- It is the CPU that shuts itself off. It has nothing to do with the OS. This is feature built into the CPU not in the OS, and its purpose is to protect the CPU from burning. When a CPU switches itself off it will make its host laptop turn off too.

In the case of intel CPUs Windows doesn't even have control of when the FAN should kick in to cool it down. The BIOS is in charge of that.

3- DTP and power consumption are not the same thing. A Core 2 Duo max DTP is 35w. It's power consumption is between 40w and little less then 60w.

 

Alright.. I'll see what I can do about the thermal paste. And the pad wasn't meant for the GPU (there was one for the GPU) because the pads were stuck onto copper heat sink bridges that were screwed into specific positions.

I haven't been able to duplicate the original problem as I posted for some reason..

I guess in the meantime would you all just recommend undervolting so it doesn't throttle so much?

Again, thanks for all the help.

Edit: Oh, and for those that are curious, the laptop shuts off upon reaching about 97 degrees (I'm looking at it when it shuts off) on both AC power and battery, so I don't think it's a faulty power supply. Intel's data sheet has TJ max at 100 C, but I don't know what that spec means.

 

Yeah undervolt it is Hope it works well for you after undervolt
Cheers!

 

The thread was written for Acers, but maybe this might prove to be of help.
ThrottleStop is one remarkable little software.

 

I nver had my laptop shutting down even when CPU reached 101C... suprising since Tjmax for T series is 105C...

and yes , try undervolting... it helps a lot... i've undervolted so much that CPU doesn't go past 80C at all... in fact 70-75C at most in games...

 

It shouldn't shut down even when it reaches 105c since Tcritic is 125c.
Reaching 105c will only make a cpu throttle down. From one of intel's datasheet:

"If Thermal Monitor automatic mode is disabled, the processor will be operating out of specification. Regardless of enabling the automatic or on-demand modes, in the event of a catastrophic cooling failure, the processor will automatically shut down when the silicon has reached a temperature of approximately 125 °C."

"Thermal Monitor" is a feature that should be built into the BIOS, but I guess it is opt to a manufacturer to impliment it or not