PC power management
Under PC power management is any type of mechanism that is intended or is used to the energy consumption of computer workstations to influence. As a rule, software puts the hardware in the lowest possible energy consumption mode under the given conditions. PC power management is therefore a sub-area of IT energy management .
Invisible energy consumption of PCs
Nowadays, the PC is a common consumer of electrical energy in the workplace in all business areas. A PC typically consumes 90 watts under load (around 50 watts for a desktop and 40 watts for a normal LCD monitor). On the other hand, it consumes only 3 to 4 watts when it is switched off. In total, up to 25% of the total energy demand of a modern office is required to supply the constantly growing IT infrastructure, computers and monitors account for almost 40% of the IT energy consumption. PC power management thus plays a key role in the energy management of buildings.
The latest research shows that considerable and unnecessary energy losses occur in the industrial economy because users do not shut down their PCs when they leave the workplace. In the UK , around £ 300 million a year is wasted on energy bills and 1.3 million tonnes of CO 2 are emitted as a direct result . In the United States, where studies show that 50% of all PCs are left on overnight, the numbers are even higher - $ 2.8 billion and 20 million tons of CO 2 per year, the equivalent of Estonia's annual CO 2 emissions.
Although the energy consumption of PCs can be reduced through low-power schemes, there are still many situations, especially in network environments, in which processes on the computer prevent a power-saving state from being reached. This in turn usually has a considerable effect on energy consumption, which the user is often not aware of. For example, although the monitor is in standby mode and the computer does not seem to be active, studies have shown that on any given day, on average, more than 50% of the PCs in an organization do not go into standby mode at all, and in the long term this affects 90 % of systems.
The actual energy consumption of "switched off" computers is therefore often significantly greater than the expected consumption.
"Endurance runner" PC
There are three reasons that prevent a PC from going into sleep mode:
- Activities of the user (keystrokes or movements of the mouse),
- CPU usage above a defined threshold or
- a process that actively requires the PC to be operational.
Further, more detailed analyzes showed that this occurs on different computers at different times of the day and night for different reasons:
- Some computers had malfunctioning mice that caused the pointer to move so that the operating system thought the mouse was moving constantly.
- Other computers had services installed that kept the computer from sleeping by periodically sending an event simulating a keystroke.
- Some applications were performing internal maintenance on a regular basis, causing spikes in CPU usage but of no real benefit.
- Still other applications (such as playing music or being in presentation mode) reported a need for system performance that prevented the computer from going into standby mode. Often this happened because the applications opened a file over the network.
solutions
It is relatively difficult to regulate the problems described and the associated waste of energy only via the energy settings of the operating system. For this reason, various manufacturers offer software solutions on the market. The more advanced users allow the network administrators to measure the energy savings achieved or to adapt the power management to the individual needs of the user by automatically waking the computer from standby mode or saving open documents.
It has been shown that using this type of energy management tool can save an average of 200 kg of CO 2 emissions and $ 35 per PC per year.
The processor of an (office) PC is generally busy waiting for user input almost all of the time. Modern processors then switch to a power-saving mode in which they hardly use any electricity, but also provide significantly less computing power; in deep “sleep states” sometimes none at all. As soon as there is work again, the processor changes back to a "higher" state in order to offer more computing power again.
- Variant 1: The processor tries to remain in the lowest possible state and to perform the task with low performance. It takes a relatively long time for this to end.
- Variant 2: Race-to-Idle - the processor immediately switches to the most powerful state in order to process the task with maximum performance as quickly as possible and to be able to fall back into a very deep sleep mode as soon as possible .
Modern PCs and notebooks generally use race-to-idle because it is more energy efficient and can perform the user job faster. However, if permanently quiet operation is necessary (e.g. no brief fan howling), variant 1 can be advantageous.
Example of incentives from politics
With the Carbon Reduction Commitment (CRC), various requirements will come into force in the United Kingdom from 2010, which for the first time force many companies to actively deal with budgeting for carbon emissions. Organizations have to buy certificates to cover their CO 2 emissions. This is linked to financial incentives for companies that emit relatively little CO 2 . Similarly, penalties are imposed for particularly high emissions.
The CRC uses energy consumption as a criterion to determine which organization falls under the new regulations, and covers all national organizations with an energy consumption greater than 6000 MWh per year (which corresponds to approximately CO 2 emissions of an estimated 1280 tons per year Year from electrical use). The organizations concerned must buy certificates for all CO 2 emissions caused . Exceptions are all emissions caused by transport. The CRC is intended to provide incentives for the efficient use of energy and to reduce greenhouse gas emissions in the non-energy sector.
As part of the CRC, measurements are also made on the supply side in order to reduce the carbon content of the energy consumed. The CRC also provides incentives for more energy efficiency on the demand side. Once quick results are achieved, more and more attention should be drawn to more difficult to achieve reductions in energy consumption. This includes all types of energy losses that are caused by the physical nature of the organization. The way in which the existing electrical equipment is used in the organization is also considered.
As tested energy management tools show, the CRC target of 4 million tonnes of CO 2 emissions saved could be achieved by 2020 simply by concentrating on optimizing all IT processes.
See also
Individual evidence
- ^ A b Mark Blackburn: Sleepless of Seattle; Why Windows Power Management Doesn't Always Work . 1E, January 2009
- ↑ 1e.com ( Memento of the original from July 5, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF)
- ^ Going Green: University of California, Berkeley .
- ↑ reliant.com ( Memento of the original from January 13, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Page no longer available , search in web archives: dell.com June 2009
- ↑ decc.gov.uk ( Memento of the original from September 19, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
