How to stop your CPU overheating without throttling…


With winter in full swing and summer seemingly a lifetime away, you may not be thinking about how hot things are getting any time soon.

Spare a thought, then, for your computer’s processor. Performing millions of calculations per second is a hot business.

The laws of thermodynamics mean that the harder your CPU works, the hotter it’s going to get.

So what is the solution?

The throttling dilemma 

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CPU throttling. This is where the computer’s management systems intervene to restrict the power supplied to the processor, giving it a split second’s rest and allowing it to cool. The downside of this, though, is that when the power is turned back on the processor begins to heat up, and the process begins again.

This seemingly never-ending cycle of power loss to the processor invariably leads to performance degradation resulting from the lower average frequencies available due to lack of power. To add to this, the hotter the CPU gets, the more it needs to throttle and so the problem is exacerbated in high ambient temperatures.

To reduce the impact of CPU throttling there are two traditional methods employed to cool CPUs, active cooling and passive cooling:

Active cooling

Active cooling employs the tried and tested technique of applying a cold source to reduce the heat, typically by blowing cool air over a heatsink. Just like when you switch the aircon on in the office so that you can perform at your best.

The problem with this method, however, is that it contains moving parts, leaving the system susceptible to more points of failure which presents a particular problem in industrial environments. A broken fan means no cooling, and no cooling means CPU throttling or even worse; system failure and costly downtime.

Passive cooling

To prevent system failure many industrial applications opt for passive (fanless) cooling. This system employs a heatsink to draw heat away from the processor and dissipate it to the surrounding air. But whilst no moving parts results in improved reliability, the size of the heatsink required is directly correlated to the amount of heat energy trying to be dissipated. This means high performance computers are typically larger than desired in many applications.

The result then is a compromise of reliability versus performance. In industrial applications where reliability is first and foremost, it is performance that takes second place as processor throttling is commonly employed as a tactic in small form factor, high performance fanless computers to keep the CPU cool.

This may be fine and well if your application doesn’t require the full performance of the CPU all of the time, however some applications demand a little bit more. This is where the risk is presented.

Applications at risk

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The risk of reducing the performance of your application as a result of thermal throttling shouldn’t be taken lightly.

Applications such as ticketing systems or self-service kiosks need to be in full and reliable operation 24/7. We’ve all felt the frustration of running to catch a train, only to miss it because the ticket machine took a long time to respond. It’s more than possible that this was caused by the CPU not performing to its optimal level due to throttling.

It’s not just customer-facing applications that require an immediate response. An industrial example is automated optical inspection – sometimes referred to as machine vision – which requires complex AI models to be processed quickly, demanding high amounts of processing power.

Another is smart parking systems that use AI or vision software to identify vehicle licence plates where the CPU needs to perform whatever the weather to avoid long queues of vehicles. These are just some examples of different applications that need optimal performance at any time.

So, if throttling isn’t appropriate, what other options do we have?

The solution 

Computer Engineering

To summarise, a variety of scenarios can determine the impact thermal throttling has on a system. Cooling solutions, ambient airflow and ambient operating temperature are the three main factors to take into consideration. In many industrial applications, active cooling is not feasible and therefore the need to look at ways of passively cooling a system whilst trying to negate the impact of processor throttling due to overheating is paramount in solution selection.

This becomes more of a challenge the smaller the system is, as the real estate required for the processor heatsink is reduced, making the air dissipation less effective.

So what is the solution? How can I cram 100 per cent of my processing performance into a small, fanless system?

First we need to look at the materials being used. A typical fanless industrial system is made from aluminium, and whilst this is a fantastic metal, strong, low cost, easy to work and corrosion resistant, it also isn’t the best choice for conducting heat. So what is? Well, gold and silver are, but 99 per cent of the time we aren’t making industrial computer systems and not contemplating the final price tag of the solution. This is where copper comes in.

Copper is over two times as efficient at transferring heat than aluminium. However it comes at a greater cost and is more difficult to work. Additionally, there are other factors to consider when using copper such as its weight which is twice as dense as aluminium/ It also has a tendency to oxidise into a nasty green colour, like a pair of cheap earrings, certainly not the look you want for your hardy industrial computer system.

The answer, then, is to look at a combination of both of these metals, maximising the conductive effectiveness of the copper to draw heat away from the processor quickly and allow it to maintain its full performance before passing that heat to a lightweight aluminium chassis. The challenge in doing this is utilising the correct combination of metals to maximise performance benefits.

Captec has taken on this challenge and designed a new range of industrial computers featuring high performance processors in a small form factor fanless design. Using a combination of copper and aluminium in an innovative heatsink design, the Captec E-Series has been designed to operate under full CPU loads in high ambient temperatures, ensuring your application gets 100 per cent of the advertised CPU performance, 24/7, even under extreme pressure in challenging environments.

With three different form factors, the Captec E-Series can also be customised and configured to the exact needs of your application.

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