ENERGY STAR* version 5.0 for desktop
ENERGY STAR v5.0 went into effect on July 1, 2009. The new specification introduces a new measurement called total energy consumption (TEC), and sets targets for four categories of desktop PCs (as compared to three categories in v4.0). New energy consumption adders for system peripherals were also added.
| Desktop | Category D | Category C | Category B | Category A |
| CPU | ≥ 4 Cores | > 2 Cores | = 2 Cores | All systems not in Cat B. C or D |
| Gfx | Integrated Gfx or Discrete GPU FBW >128-bit | Integrated Gfx or Discrete GPU | Integrated Gfx | |
| Memory | ≥ 4 GB memory | ≥ 2 GB memory | ≥ 2 GB memory |
| Platform | Power Supply | Requirements | Capability Adjustments |
| Desktop, Integrated DT |
82-85-82% efficiency (20-50-100% load) and ≥ 0.9 PFC @100% rated output |
TEC (kWh) Cat A: ≤ 148 Cat B: ≤ 175 Cat C: ≤ 209 Cat D: ≤ 234 | Memory: 1 kWh (per GB over base) Base Memory: Cat A, B, C = 2GB; Cat D = 4GB Discrete GPU (FB Width): Cat A, B: 35 kWh (≤ 128-bit); 50 kWh (>128-bit); Cat C, D: 50 kWh (>128 bit) Additional storage: 25 kWh |
| TEC Weighting | ||
| Conventional | Proxying | |
| Toff | 55% | 40% |
| Tsleep | 5% | 30% |
| Tidle | 40% | 30% |
To calculate the overall TEC value, use the following formula with the power consumption data gathered from testing:
ETEC = (8760/1000) * (Poff * Toff + Psleep * Tsleep + Pidle * Tidle)
Most systems should be tested under conventional weighting, See specification for more details (PDF 1.09MB).
As shown in the table above, a new weighting will be available for PCs which enable network proxying and full network connectivity. Systems must meet proxying standards approved by the EPA and the European Union, such as ECMA, to qualify for the proxying measurements.
Component selection
ENERGY STAR v5.0, like its predecessor, is a system-level self-certification. No individual component is "ENERGY STAR compliant," therefore system integrators should choose components which will help them reach their energy consumption goals.
Any of Intel's processors and motherboards can be used in an ENERGY STAR system. However, several products have features such as lower idle power, lower TDP, and smaller form factor that help meet the requirements more easily. Refer to the current eco-smart product roadmap for a list of products 
(PDF 403KB).
It is important to choose a power supply that fits your system. For ENERGY STAR v5.0, the following table shows the internal power supply requirements for desktop PCs. In addition to the efficiency, a good tip is to choose a power supply with the lowest wattage that will support your system configuration. Efficiency quickly drops below the 20% load, so a typical system designed for ENERGY STAR will work well with a power supply size of 200W-300W.
| Load | Efficiency |
| 20% | 82% |
| 50% | 85% |
| 100% | 82% |
Power factor ≥ 0.9 at 100% of rated output
Please note that these requirements fulfill the 80 PLUS* Bronze power supply logo requirements; however, the power supply does not need the actual 80 PLUS certification to meet ENERGY STAR requirements.
Desktop testing services
For US partners, Premio, Inc. offers an in-house ENERGY STAR testing service.
ENERGY STAR documentation
ENERGY STAR* System Implementation Whitepaper (PDF 1.01MB)
ENERGY STAR* 4.0 Specification (PDF 744MB)
ENERGY STAR* 5.0 Specification (PDF 1.09MB)
ENERGY STAR web sites
ENERGY STAR*
80 PLUS* power supplies
ENERGY STAR* Intel® tested power supply list