ARGH!! 2.40Ghz CPU not running above 1.2Ghz

SuprSi

I'm at my wits end with this. I have a 5 year old Samsung laptop running Windows 10, with an SSD. It still runs perfectly well, however for a good while now the CPU is running slower than I need it to.

It's a 2.4Ghz CPU, and even with intensive tasks that need more than 1.2Ghz, it won't go up! I've had rare occasions whereby the CPU will go up over 3Ghz, but it's very rare.

I've tried changing the Windows power settings. I've tried disabling Intel Turbo Boost. I've tried overclocking the CPU. At one point I modified a registry setting that made sure the CPU ran at 2.4Ghz, but I can't remember it!! Would love if someone could point me in the right direction.

stupid question, more for my own curiosity- what RAM profile?

TerrorFirmer

What model CPU is it, what laptop? It's likely either a) the laptop's cooling is not working correctly or b) it's not a great laptop and the cooling was never sufficient to allow boosted speeds.

Either is very common to be honest. Mobile CPU's have a base clock and a boost clock. In older machines it's very common for the boost to be unsustainable for more than a minute or two, if even. Even in 2019 you can get machines with CPU's that rarely go above their base clock due to poor thermals.

SuprSi

It's got 8Gb RAM, which is quite heavily utilised when I'm using Ableton (which is what I need the poke for). The CPU is an Intel Core i7-3635QM. It's supposed to burst to a higher lock speed when required, but even if I use an actual Intel tool and run a CPU stress test, it still won't go above 1.2Ghz.

The crazy thing is it randomly does it - last week, on Wednesday, I didn't do anything different, and the CPU was running at 3.2! I know that's not sustainable, but I'd love to get it back to 2.4 as it's killing Ableton.

TerrorFirmer

Have you checked the thermals? It's possibly throttling due to the temperatures. These often don't have to be sky high - on laptops there's often an in-built cutoff where it throttles long before actual dangerous temps, and given the age of that CPU it could probably do with a proper clean and fresh thermal paste.

SuprSi

That's an interesting thought. The CPU generally hovers around 60c, but I've never taken the lid off the thing so will have a look.

SuprSi

I found the registry settings;

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Processor\Start
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\intelppm\Start

Both of these were set to 3 - setting the to 4 and restarting makes the CPU run at 2.40Ghz. CPU temperature has increased, but only up to 72C, even under load, which is cool, though I'll keep an eye on it over the rest of the week just in case.