We intend the following information for professional system integrators using systems with Intel® Processors.
Integrators who follow these thermal management recommendations can provide their customers with more reliable PCs and have fewer customers returning with problems.
What is thermal management?
Laptops using mobile Intel Processors require thermal management. The goal of thermal management is to keep the processor at or below its maximum operating temperature (case). Thermal management refers to two major elements:
- A cooling solution properly mounted to the processor
- Effective airflow through a part of that cooling solution to evacuate heat out of the system.
What is active cooling?
For higher power processors today, almost all laptops employ some form of an active cooling solution. You can accomplish active cooling in one of two ways:
- Have a heatsink attached directly to the processor.
- Use a Remote Heat Exchanger (RHE). An RHE offers more flexibility in thermal design. You can place the actual heatsink and fan far from the processor.
A typical solution for laptop cooling is far more sophisticated than a solution for desktop systems. Laptop cooling solutions vary greatly between laptops from different manufacturers because of:
- Limited space
- Varying laptop design
- Processor location
Although the RHE design is efficient, some laptop designs use the RHE design with a passive element to increase the cooling efficiency of the solution. Usually to add a passive element, a large metal plate is attached to a part of the RHE design. The plate allows more heat to dissipate passively, typically from under the keyboard.
What is a heat pipe?
Heat transfers from the processor to an attachment block, through which runs a heat pipe. A heat pipe is typically a hollow copper pipe containing a fluid and wicking material. Through vaporization and recondensation, heat travels through the heat pipe to heatsink fins. Localized airflow then evacuates the heat to the outside air.
What is thermal interface material (TIM)?
Highly efficient cooling solutions rely heavily on proper processor installation to work. In all laptop designs after installing the processor, it must attach to the laptop cooling solution. Generally, a thermal interface material (TIM) is used to provide efficient thermal exchange between the processor and attachment block. The type of thermal interface material may vary depending on the laptop manufacturer. Proper installation of this thermal interface material is crucial to the success of the thermal solution. Failure to properly install the thermal interface material could cause the processor to overheat. We recommend you:
- Follow the manufacturer's instructions carefully.
- Ensure the thermal interface material makes complete contact with both:
- The exposed die of the processor
- The thermal attachment block of the laptop.
- Never touch the thermal interface material. Foreign substances such as oils from your skin or chemicals can reduce the effectiveness of the thermal contact between the processor and the attachment block.
|Note||If you remove the TIM from the processor, you may need to replace the TIM. The TIM of different manufacturers has varying thickness and thermal properties. Contact your laptop vendor, manufacturer, or the place of purchase for replacement.|
Do I have to replace the TIM if I replace my mobile processor?
If you remove the thermal solution for a mobile processor, you should replace the thermal interface material (TIM).
Where do I get TIM?
Each laptop has different size restrictions and thermal requirements, so the laptop vendor or manufacturer must provide the thermal solution. Different from boxed desktop products, the thermal solution is not provided.
What is a thermal transfer plate?
The thermal transfer plate (TTP) provides heat dissipation for the Intel® 443 BX host bridge and the processor chip, made of a copper alloy. Underneath the thermal transfer plate, there is thermal grease to give the plate better thermal connectivity.
What is a thermal sensor?
The mobile Intel Processors incorporate an on-die diode used to monitor the die temperature (junction temperature). A thermal sensor on the motherboard or a standalone measurement kit may monitor the die temperature of the mobile processor. You can use the sensor or kit for thermal management or instrumentation purposes.
What is thermal testing?
Integrators building mobile Intel® Processor-based laptops should consult their manufacturer to determine the highest power processor your laptop supports. Most laptops support throttling, a method of slowing down the processor if it exceeds its maximum operating temperature. Throttling may cause a reduction in performance and we do not recommend relying on it to manage the processor thermal solution.
If you have correctly installed the processor and the system is designed to accommodate the processor power, you may not need thermal testing. Nonetheless, your laptop manufacturer may provide software utilities to assist in monitoring the processor temperature. Mobile Intel Processors have built in thermal diodes. Most laptops have built in circuitry to monitor processor temperatures by converting the diode reading into a real temperature. Consult your laptop manufacturer for availability of a thermal monitoring utility.
Using thermocouples to measure processor temperature may be impractical. Any attachment of thermocouples likely compromises the performance of the thermal solution.
Refer to Intel Atom® Processor datasheets for more information about:
- Thermal specifications
- Processor power specifications
- Enhanced Intel SpeedStep® Technology (EIST)