Laptop cooling
 

Anyone using their laptop for calculations should get an external laptop cooler.

I have a 4 year old Dell XPS L702X (Sandy Bridge Corei7 2720QM). A while ago I had a cheap external cooler but at the time I was not running Prime95, so I did not test the difference in speed with or without the cooler. The fans in the cooler started making noise so I stopped using it and threw it out and did not get one for a while.

Now I was using Prime95 on a small 16.5M exponent for the triple check project and I thought it felt slow. I just got a new external cooler 2 days ago I did not even open yet: [URL="http://www.coolermaster.com/mobile/notepal-series/notepal-x3/"]Notepal X3[/URL]. Here in Denmark it cost 299 dkk (~ $43). (I'm not getting any money for advertising this product :smile: )

The average iteration times over 10,000 iterations was 7.7 ms without any external cooler, and now with the Notepal it is 3.7 ms! So slightly more than twice as fast.

Your laptop cooling might just suck. I did the same thing on a mid 2014 macbook pro. bought a coolermaster x-slim and a sf-19 and neither of them increased performance much. There's a sweet spot while changing the fan speed on the sf-19 where I go from 2.4 to 2.5 Ghz a little bit more often, but other than that... I actually lose performance on the sf-19 if I turn all the fans up.:banana:

For what your average non-power user does with their laptop, the energy saving functions are a complete no-brainer. For surfing, e-mail and the occasional spreadsheet, 1.0 GHz on a modern, more computationally efficient CPU with a couple of cores is plenty. This is what unlocks the 8-hour battery life.

The cool thing about these functions is that they can be disabled to unlock the full potential of the CPU, as much as doubling or even tripling the speed (at the expense of several times more heat; huge diminishing returns there). When the energy-saving functions are disabled, core frequency is increased and the voltage is notched up accordingly, up to a certain threshold. If the CPU is uncomfortable with the temperature, it will not further increase the frequency or voltage and you'll have hit your limit.

On the other hand, if you use a better cooling solution, that threshold will only be met at a higher performance level. In many respects this is the same thing as thermal throttling except that it starts at the bottom and works its way up under a heavy workload whereas the throttling generally starts at the maximum performance level and reduces power until a happy temperature is achieved.


With that being said, not all laptops will benefit from additional cooling. Mine was good enough that the CPU would hit the factory max well below any temperature threshold.

Also, under windows, there are advanced power options which can limit the CPU frequency at the OS-level.

On my now-dead (fried mobo) 2009 MacBook Core2 duo I replaced the fan several times - even with regular dedusting the dust clogs eventually strain the el cheapo fan and bearing too much. What I eventually found to work well:

a. Don't run anything heavy while using the laptop;

b. When not using, leave lid open ~30 degrees and prop unit in 'A-frame' mode, with the rear exhaust vent on top. That allows passive convection and free airflow thru the keyboard (which acts as the main air intake) to help the fan as much as possible, and helps keep dust out of the fan, since rather than simply 'falling' in thru the KB the dust now needs to travel first down then back up to get in. Some will still be carried along by the convective airflow, but not as much.

(NB: My refurb replacement is a 2009 Core (not Core2) duo, whose horrid half-bandwidth sse2 makes running Prime95 a non-starter.)

Macs don't use keyboards for airflow - this is a myth, although it'll run slightly cooler with the lid open. The inlets are on the sides.

[QUOTE=ewmayer;397955]b. When not using, leave lid open ~30 degrees and prop unit in 'A-frame' mode, with the rear exhaust vent on top.[/QUOTE]I found that completely closing a laptop and placing it upside down gives the best cooling for a wide range of models and brands. But you'll need to find the option to tell the OS to take no action when the lid is closed. If you use a USB keyboard and external monitor you can still use it for other functions also.

[QUOTE=retina;397964]I found that completely closing a laptop and placing it upside down gives the best cooling for a wide range of models and brands.[/QUOTE]

I found the best solution is to close your laptop, power it down, and never open it again.

Minions use laptops.

Edit: Superusers use pads of paper and a pen when in a meeting.

[QUOTE=aurashift;397963]Macs don't use keyboards for airflow - this is a myth, although it'll run slightly cooler with the lid open. The inlets are on the sides.[/QUOTE]

Thanks- you are of coures correct, not sure what I had in mind when I blurted that out. The keyboard''s Alumin(i)um baseplate acts as a passive heat dissipater - the Copper heat pipes from both CPU and WiFi card run directly underneath it, so that would seem to work best in the usual in-usage mode, keyboard horizontal.

I do distinctly recall seeing less dust accumulation in the fan after switching to the 2-step method I described, but perhaps that is simply from the reduced hours of daily usage.

[QUOTE=chalsall;397965]I found the best solution is to close your laptop, power it down, and never open it again.

Minions use laptops.

Edit: Superusers use pads of paper and a pen when in a meeting.[/QUOTE]

I very much like this quote. It isn't 100% true but it's close. There was one class in my entire four years of school where I preferred to type for my notes. There would have been at least thirty where I would have hated life if I had to type my notes.

Still, you can't beat laptops for applications that require mobility and aim for highest computing power (i.e. a gaming PC you can bring to places with you).


[QUOTE=retina;397964]I found that completely closing a laptop and placing it upside down gives the best cooling for a wide range of models and brands. But you'll need to find the option to tell the OS to take no action when the lid is closed. If you use a USB keyboard and external monitor you can still use it for other functions also.[/QUOTE]

Hmmm... A black box in which you plug a keyboard, a mouse and a monitor and then use for various applications.


I have one of those. I call it a desktop.

[QUOTE=TheMawn;397976]Hmmm... A black box in which you plug a keyboard, a mouse and a monitor and then use for various applications.[/QUOTE]Works for other [strike]colors[/strike] colours also.

[QUOTE=ewmayer;397967]Thanks- you are of coures correct, not sure what I had in mind when I blurted that out. The keyboard''s Alumin(i)um baseplate acts as a passive heat dissipater - the Copper heat pipes from both CPU and WiFi card run directly underneath it, so that would seem to work best in the usual in-usage mode, keyboard horizontal.

I do distinctly recall seeing less dust accumulation in the fan after switching to the 2-step method I described, but perhaps that is simply from the reduced hours of daily usage.[/QUOTE]

Oh, forgot. I also have a little usb fan blowing on the keyboard during night crunching. :banana:

I'm curious to try that upside down trick. I'm curious if it'll do anything with a laptop cooler on it too.