RPICT03/07: Overview of MTP Laptop Computer Testing Activities and Results

Transcription

1 RPICT03/07: Overview of MTP Laptop Computer Testing Activities and Results

2 RPCEXX/06: Overview of MTP Laptop Computer Testing Activities and Results 2

3 Executive summary This report gives an overview of MTP testing 1 results on laptop computers and provides analysis of results against the ENERGY STAR criteria for computers. The results were submitted to the US Environmental Protection Agency (EPA) to assist it with setting criteria for the ENERGY STAR label. In total, 36 laptop computers were tested between April 2006 and March These were categorised by the sample provider for magazine publication purposes. The five categories were Ultraportables, Student notebooks , Dual-core notebooks under 1,200 and a second group of ultraportable laptops called Ultraportables 2. In standby (off mode), all laptop computers tested consumed fewer than 3 W. The ENERGY STAR criterion of 1 W is slightly higher than the lowest consuming 25% of models (0.83 W). The majority of samples tested had sleep-mode levels below 2 W. Half of the tested samples were below the ENERGY STAR level of 1.7 W. Some of these were highly specified laptop computers, so it would seem that this level of sleep-mode power consumption is achievable even with highly specified hardware. The most power hungry laptop computers in idle mode used between W and W. These were all in the Dual-core notebooks under 1,200 category tested in September 2006, which featured the latest mobile dual-core processors. The laptop computer with the least power consumption in idle mode (7.97 W), was from the Student notebooks category tested in July The rest of the leastpower-consuming laptops in idle mode were from the Ultraportables and Ultraportables 2 categories tested in May and November 2006 and used between 8.86 W and W. Laptop computers compare favourably with desktops in terms of energy consumption. In fact, even the highest consuming laptop computers consumed less in idle mode than the lowest consuming desktop computers that were tested in the same year 2 1 As part of ongoing computer testing (at MTP consortium partner Intertek) there has been the opportunity to run power measurements on samples as they come into the laboratory. This greatly reduced the cost of compliance testing as the purchase of samples was not required. 2 RPICT02/07 Overview of MTP Desktop Computer testing activities and results

4 Table of contents 1 Background 1 2 Breakdown of quantity by category Description of categories 2 3 Power modes On Mode Sleep Modes Standby (Off Modes) 3 4 Power measurements Test methodology followed Test methodology observations 6 5 Results summary Hard off Standby (off mode) Sleep mode Idle mode 12 6 Conclusions Move to dual-core laptops resulting in trend towards increased consumption Adequacy of the current Tier 1 ENERGY STAR specification Disparities in power consumption modes 15 7 Glossary 17 4

5 1 Background As part of a programme of on-going computer testing 3, MTP has had the opportunity to carry out compliance testing on batches of samples, available for only a limited period in the testing lab, during which time power measurements and other commissioned tests had to be performed. 2 Breakdown of quantity by category Laptop computers were tested in batches, categorised as Ultraportables, Student notebooks , Dual-core notebooks under 1,200. A second group of ultraportable laptops called Ultraportables 2 were new to the market and, as such, reflected, as near as possible, up-to-date consumer configurations. In total, 36 laptop computers underwent power measurement tests between April 2006 and March One sample in the Student notebooks category was removed from the following results and analysis as it would not allow the screen to turn off during the idlemode test. Table 2.1 Breakdown of quantity by category Laptop computer category Date tested Number of samples Ultraportables 02/05/ Student notebooks /07/ Dual-core notebooks under 1,200 14/09/ Ultraportables 2 14/11/ TOTAL 35 3 As part of ongoing computer testing (at MTP consortium partner Intertek) there has been the opportunity to run power measurements on samples as they come into the laboratory. This greatly reduced the cost of compliance testing as the purchase of samples was not required. 1

6 2.1 Description of categories The categories were constructed by the sample provider for purposes of group testing for magazine reviews. The laptop computers in the Student notebooks and Dualcore notebooks under 1,200 price categories excluded VAT and delivery. The categories in Table 2.1 are in the sequence in which they were tested. Due to the rapid increase in performance of available computer hardware over time, a highly specified laptop computer could, in a few months time, be considered a typically specified laptop computer. The terms laptop and notebook are interchangeable in this document Ultraportables As the Ultraportables were small and light laptop computers, they were well suited to being carried from place to place. The weights were between 1.35 kg and 2.15 kg including the batteries. They were all between 30 to 40 mm thick and included mobile processors with one or two cores and integrated graphics controllers. Most had 512 MB of random access memory (RAM), but two had 1 GB of RAM. They had 60 GB to 100 GB hard disc drives (HDD). None of these samples had wide screens Student notebooks Computers in this category were designed to be sold in the 499 to 699 price range (excluding VAT and delivery) to appeal to students budgets. These had mobile processors with one or two cores. Most had an integrated graphics controller, while one had a separate graphics card. Most had 512 MB of RAM, but four had 1 GB of RAM. They had 40 GB to 100 GB HDDs Dual-core notebooks under 1,200 These computers were priced at under 1,200 (excluding VAT and delivery). They all featured the new, mobile, dual-core processors with 512 MB to 2 GB of RAM and HDDs of 80 GB to 120 GB. Half had integrated graphics controllers and half had separate graphics cards Ultraportables 2 Like the Ultraportables category, these computers were small and light, weighing between 1.9 kg and 2.4 kg, and were 28 mm to 43 mm thick, so were well suited to being carried from place to place. They all featured processors with two cores and a reasonable amount of RAM (512 MB to 1 GB) HDDs of 80 GB to 120 GB). 2

7 3 Power modes Laptop and desktop computers consume different amounts of energy depending on their modes of operation. In general, they consume most energy when they are in the on mode, actively performing tasks such as writing to a DVD recordable disc. They consume the least energy when they are in standby (off mode) or in sleep mode. 1.1 On Mode This is the state in which the computer is connected to the mains power supply and has fully loaded the operating system. Testing has shown that idle mode is broadly representative of the consumption levels that would occur when the computer is being used for non processing-intensive tasks, such as , word processing and internet browsing. 1.2 Sleep Modes There are several low power mode states that a computer can be in. For example, sleep mode is a low power mode from which the computer can quickly be returned to its on mode, without having to reboot the operating system. Sleep mode can further be divided into four types of ACPI modes as described below S1 and S2 S1 halts the processor and S2 powers down the processor. Due to development of more sophisticated power management these tend to be found mainly on older computers S3 S3 is the most common sleep mode and is often referred to as suspend to RAM (STR). In this state, information about the computer s state is stored and retained in RAM and can quickly be read back when the computer returns to the on mode. The RAM must be powered to retain this information. It is important to note that in Microsoft Windows, this is referred to as the standby mode. 1.3 Standby (Off Modes) S4 S4 is also referred to as hibernate mode and is an extension of the S3 (sleep mode) and has similarities to S5 mode below. Instead of storing the computer s state in RAM (as happens in S3 mode) which allows for fast wake-up from sleep mode, but requires additional power to retain the information, it is stored on the computer s HDD. This can require less power, but takes slightly longer for the information to be read back from the HDD when the computer returns to its on mode. In some instances, S4 can even consume the same or less power than in standby (off) mode, due to some components, 3

8 such as the network interface card being in a low power state in sleep mode, but having no power management in standby mode S5 This mode, often referred to as advanced configuration and power interface (ACPI 4 ) mode S5, is generally the lowest power mode. However, these tests indicate that this is not always the case. The computer is connected to the mains power supply, but has undergone an operating system shut down procedure. The S5 mode, unlike S4 or S3 (described below) does not save any data relating to the computer s state. In Microsoft Windows, this is the state when shut down is selected. To return to the on mode, the computer has to boot the operating system. See Table 3.1 for a full explanation of the different power modes. Laptop power measurements were taken in the following power modes: Hard off. Standby (off mode). Sleep mode. Idle mode Table 3.1 Power mode Hard off Standby (off mode) Sleep mode Idle mode General ENERGY STAR definitions Description In the case of desktop PCs, this is when the desktop PC is connected to a mains supply, but the power supply switch is in the OFF position. In the case of laptop PCs, this is when the external power supply is connected to the mains supply, but is not connected to the laptop. The power consumption level in the lowest power mode that cannot be switched off (influenced) by the user and that may persist for an indefinite time when the appliance is connected to the main electricity supply and used in accordance with the manufacturer s instructions. For purposes of this specification, the standby (off mode) correlates to ACPI System Level S4 or S5 states, where applicable. (This is NOT the same as putting Microsoft Windows into standby) A low-power state that the computer is capable of entering automatically after a period of inactivity or by manual selection. A computer with sleep mode capability can quickly wake in response to network connections or user interface devices. For the purposes of this specification, sleep mode correlates to ACPI System Level S3 (suspend to RAM) state, where applicable. (This is the same as putting Microsoft Windows into standby). For purposes of testing and qualifying computers under this specification, this is the state in which the operating system and other software have completed loading, the machine is not asleep, and activity is limited to those basic applications that the system starts by default. A period of 15 minutes must elapse from the time the computer is switched on and the measurement is integrated over the following five minutes. An arithmetic mean value is quoted as the result. 4 For an explanation of ACPI please refer to 4

9 4 Power measurements Power measurements were taken using a calibrated power analyser. A voltage stabiliser was also used to regulate the mains supply voltage to 230 V during testing. Measurements were recorded in watts, rounded to two decimal places and were integrated 5 over five minutes. 4.1 Test methodology followed Each sample was connected to a 230V mains supply via the voltage stabiliser, with the power analyser set to take measurements. The laptop computer s internal batteries were removed during testing as per the Final Version 4.0 of the ENERGY STAR test methodology. For tests carried out before 1 January 2007, the samples were left for five minutes, as per the ENERGY STAR DRAFT Version 2.0 test methodology, before integrating a power measurement over five minutes. For tests carried out after 1 January 2007, the samples were left for 15 minutes, as per the Final Version 4.0 of the ENERGY STAR test methodology, before integrating a power measurement over five minutes Hard off In the case of laptop computers, this was measured with the external power supply connected to the mains supply, but not connected to the laptop computer. This is a measure of the energy that the power supply units (PSUs) consume Standby (off mode) This was measured by turning the sample on, allowing it to fully boot into Microsoft Windows and then powering it off via the start menu (start/shutdown). A measurement was then taken. In this mode, the computer s motherboard and internal components consume a small amount of energy Sleep mode This was measured by turning the sample on, allowing it to fully boot into Microsoft Windows and then putting it into standby mode (sleep mode) via the start menu (start/shutdown). A measurement was then taken. This is mainly a measure of the energy consumed by the computer s motherboard, RAM and any other components that are in a low power state (e.g. a network interface card (NIC)). One sample from the Ultraportables 5 Integrated values are the average energy consumption over a user selected time interval. 5

10 2 category was tested with both Mac OS X Tiger and Microsoft Windows XP Pro SP2 under Boot Camp Idle mode This was measured by turning the sample on and allowing it to fully boot into Microsoft Windows. The integrated laptop screens were set to turn off after one minute of inactivity and were off during the measurement. Idle mode is indicative of the energy consumed by the computer s motherboard and other internal devices when the computer is switched on. This value will be higher for computers with a larger number of high-power-consuming internal devices. The more RAM, video RAM 8, and HDDs, the greater the computer is likely to consume in idle mode. One sample from the Ultraportables 2 category was tested with both Mac OS X Tiger and Microsoft Windows XP Pro SP2 under Boot Camp. 4.2 Test methodology observations The network interfaces speed is sometimes reduced in sleep mode, but not in standby mode, resulting in higher power consumption in the lowest power mode (standby mode) than in sleep mode. The Final Version 4.0 of the ENERGY STAR test methodology requires turning off the wireless network hardware (where available) during testing. Current market trends may warrant the opposite approach for a truer measurement, in the same way that the wired network hardware must be configured with a similarly capable network switch during measurements. Many of the laptop computers came with wireless networking connectivity. MTP will continue to submit results to the US Environmental Protection Agency (EPA) to assist it in its assessment of the ENERGY STAR label criteria and to the European Computer Manufacturer s Association (ECMA) to assist it in developing benchmark-based approaches for subsequent ENERGY STAR Tiers. 6 Mac, Mac OS and Tiger are trademarks of Apple Inc, registered in the US and other countries. 7 Boot Camp is a registered trademark of Apple Inc, registered in the US and other countries. It is beta software that allows a Mac computer with an Intel processor to boot a Microsoft Windows operating system. 8 Also a discrete, rather than integrated, graphics processing unit has an impact. 6

11 5 Results summary An analysis was carried out on the best and worst-performing laptop computers in each power mode where there were data available to perform the analysis. The figures below apply to the five lowest recorded measurements, the five highest recorded measurements and an overall average of all measurements. See Table 5.8 for the full table of results. 5.1 Hard off This measurement does not form part of the ENERGY STAR criteria, but could be regarded as providing useful data as this is the minimum amount of power a laptop computer could consume with the supplied external PSU. All except one of the tested samples consumed fewer than 0.63 W. One sample slightly exceeded the 0.75 W ENERGY STAR criterion for no-load power consumption for external PSUs. Table 5.1 Hard-off results summary Hard Off Measurement Observations Lowest power consumption 0.25 W This laptop computer from the Ultraportables 2 category had a 3.75 A external PSU and was tested in November 2006 Average power consumption 0.46 W Highest power consumption 0.79 W This laptop computer from the Ultraportables category tested in May 2006 had an external 3.16 A PSU 7

12 5.2 Standby (off mode) Table 5.2 Standby (off mode) results summary Standby (Off Mode) Measurement Observations Lowest power consumption 0.44 W to 0.68 W The sample that measured 0.44 W was the same sample that had the lowest hard off power consumption. Ten of the 35 samples measured less than 1 W and 15 measured between 1 W and 2W. Average power consumption 1.56 W Highest power consumption 2.58 W to 2.84 W The laptop computer with the highest measured standby (off mode) level was not a very highly specified laptop computer, it was from the Student notebooks category tested in July 2006 and had a 3.42A external PSU. Ten of the 35 samples measured more than 2 W The results below show that there is little evidence to suggest a link between specification level and standby power consumption in laptop computers. In this mode, power is predominantly consumed by the PSU, motherboard and network card. Table 5.3 Standby (off mode) average results summary Laptop computer category Date tested Average standby (off mode) power consumption (W) Ultraportables 02/05/ Student notebooks /07/ Dual-core notebooks under 14/09/ ,200 Ultraportables 2 14/11/ The following scatter graph illustrates the lack of correlation between standby consumption and specification level. All standby (off mode) levels were less than 3 W and 31% of samples were below the ENERGY STAR threshold of 1 W. This would indicate that there is more scope for improvement in the criteria for standby consumption, and that ENERGY STAR criteria could be strengthened to further influence the market. 8

13 Figure 5.1 Standby (off mode) of all samples Ultraportables Student Notebooks Dual Core Notebooks under 1200 Ultraportables 2 Watts (W) Average of test results Energy Star requirements Lowest 25% of test results RAM*PSU (VA) 9

14 5.3 Sleep mode Table 5.4 Sleep-mode results summary Sleep mode Measurement Observations Lowest power consumption 0.94 W to 1.14 W Four out of the five samples were either from the Ultraportables category tested in May 2006 or from the Ultraportables 2 category tested in November The sample with the lowest sleep mode consumption was from the Student notebooks category tested in July 2006 and had a dual-core processor with 512 MB of RAM and an integrated graphics controller. Average power consumption 1.79 W Highest power consumption 2.75 W to 3.75 W The sample with the highest sleep mode power consumption was from the Student notebooks category tested in July 2006 and had a dual-core processor with 1 GB of RAM and an integrated graphics controller. Only motherboard and RAM are powered in this mode. The laptop category with the more basic specification level (Student notebooks ) contained the sample with the lowest measured sleep mode consumption. However, the overall average sleep-mode consumption for this category was actually the highest of all the categories. This was surprising as the samples with the highest specifications would usually be expected to consume the most power. Table 5.5 Sleep-mode average results summary Laptop computer category Date tested Average sleep mode power consumption (W) Ultraportables 02/05/ Student notebooks /07/ Dual-core notebooks under 14/09/ ,200 Ultraportables 2 14/11/ The following scatter graph shows that the majority of samples tested had sleep-mode levels below 2 W. Half of the tested samples were below the ENERGY STAR level of 1.7 W, indicating that ENERGY STAR criteria could possibly be more stringent. Note that as the scatter of categories is wide, it is clear that higher specification does not necessarily result in high power consumption. 10

15 Figure 5.2 Sleep mode of all samples Ultraportables Student Notebooks Dual Core Notebooks under 1200 Ultraportables Watts (W) Average of test results 1.50 Energy Star requirements 1.00 Lowest 25% of test results RAM*PSU (VA) 11

16 5.4 Idle mode Laptop computers compare favourably with desktops in terms of energy consumption. In fact, even the highest consuming laptop computer (35.63 W) consumed less power in idle mode than the lowest consuming desktop computer (56.52 W) that was tested in the same year 2. Table 5.6 Lowest power consumption Average power consumption Highest power consumption Table 5.7 Idle-mode results summary Idle mode Measurement Observations 7.97 W to Four out of the five samples were either from W the Ultraportables category tested in May 2006 or from the Ultraportables 2 category tested in November The sample with the lowest idle mode consumption was from the Student notebooks category tested in July 2006 and had a dual-core processor with 512 MB of RAM and an integrated graphics controller W W to W Idle-Mode average results summary Four out of the five samples were from the Dual core notebooks under 1,200 category tested in September The sample with the highest power consumption had a dual-core processor with 1 GB of RAM. Laptop computer category Date tested Average idle mode power consumption (W) Ultraportables 02/05/ Student notebooks /07/ Dual-core notebooks under 14/09/ ,200 Ultraportables 2 14/11/ The following scatter graph shows that the majority of samples tested have idle-mode levels between 10 W and 20 W. The grouped distribution of the sample categories would indicate that the ENERGY STAR approach of defining specific minimum criteria for high and low specified computers is justified. 12

17 Figure 3 Idle mode of all samples Ultraportables Student Notebooks Dual Core Notebooks under 1200 Ultraportables 2 Watts (W) Energy Star High Spec requirements Average of test results Energy Star Low Spec requirements Lowest 25% of test results (RAM+Video RAM)*Cores*PSU (VA) 13

18 Table 5.8 Ultraportables Student notebooks Dual-core notebooks under 1,200 Ultraportables 2 Table of results Standby Mode (W) Sleep Mode (W) Idle Mode (W) Sample Category Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables average Student notebooks Student notebooks Student notebooks Student notebooks Student notebooks Student notebooks Student notebooks Student notebooks Student notebooks Student notebooks average Dual-core notebooks under 1, Dual-core notebooks under 1, Dual-core notebooks under 1, Dual-core notebooks under 1, Dual-core notebooks under 1, Dual-core notebooks under 1, Dual-core notebooks under 1, Dual-core notebooks under 1,200 Dual-core notebooks under 1, average Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables Ultraportables 2 average OVERALL AVERAGE 14

19 6 Conclusions This study has not aimed to cover the full range of the laptop PC market. However, these tests cover laptop computers over a wide range of prices and specifications, and some valuable conclusions can be drawn from the test result data. 6.1 Move to dual-core laptops resulting in trend towards increased consumption The test results illustrate that Dual-core notebooks under 1,200 and the Ultraportables 2 were the highest consuming laptop computers, although for modes such as sleep and standby (off mode) there can be widely ranging consumption regardless of specification (suggesting that consumption in these modes is not dependant on specification). 6.2 Adequacy of the current Tier 1 ENERGY STAR specification The spread in consumption highlights the need for a label that can push product manufacturers to move towards more efficient designs. The ENERGY STAR approach for the computer specification appears to have scope for further stringency in a subsequent revision, as criteria appear to be matching the level of the lowest consuming 50% of the market in sleep mode and idle mode, rather than the target 25% market level. The average hard-off mode consumption of the tested samples was 0.46 W, with the threshold of the lowest consuming 25% sitting at 0.4 W. All, except one, of the laptop computers consumed below the ENERGY STAR criterion for no-load power consumption for external power supplies of 0.75 W. For standby (off mode), some laptops easily met the ENERGY STAR criterion (1 W), with the lowest consuming 25% of models consuming 0.83 W or fewer. However, many laptop computers tested consumed significantly higher, taking the average up to 1.56 W. For sleep mode, half of the tested samples consumed fewer than the ENERGY STAR 1.7 W requirement so there would seem to be room for criteria revision here. However, reducing requirements to below 1 W may not be cost-effective and measurement of levels much below 1 W would be more challenging due to accuracy and repeatability issues. For idle mode, the ENERGY STAR requirement (14 W to 22 W depending on specification) could be strengthened further as almost half of the laptop computers tested were below the 14 W threshold. Most of the laptops were grouped together in the 10 W to 15 W range, except for some of the higher specification Dual-core notebooks under 1,200 category. Six of the highly specified laptop computers consumed fewer than the 22 W threshold. It appears that there may be some kind of correlation between idle-mode consumption and capability, which would back the EPA s approach to divide the criteria into low and high-specification models. 6.3 Disparities in power consumption modes 15

20 Surprisingly, some laptop computers consumed more power in standby (off mode) than in sleep mode. It would appear that this may be due to there being a level of power management in sleep mode and no power management present in standby (off mode). For example, the laptop could be putting devices into low power states in sleep mode (i.e. reducing the network interface speed) and not managing their power at all in standby (off mode). 16

21 7 Glossary CPU GPU HDD Motherboard Multi-core processor PSU RAM Central processing unit Graphics processing unit (processor dedicated to performing calculations related to displaying computer graphics sometimes integrated onto motherboard) Hard disk drive (non-volatile storage device that stores data magnetically on rotating platters) The main printed circuit board that holds the CPU, RAM and other essential components. Other components such as the HDD, GPU and PSU also connect to the motherboard CPU containing two or more processors as in dual-core or quad-core Power supply unit (converts mains voltage to low voltages used by the computer components) Random access memory (volatile memory used for loading, displaying and manipulating applications and data) 17

22 Contact: Market Transformation Programme AEA Energy & Environment The Gemini Building Fermi Avenue Harwell Didcot OX11 0QR MTP Helpline Tel: +44 (0) Report ID: ICT/03/07 March2008