In a move to reduce computer power consumption, Intel, Santa Clara, Calif. (www.intel.com), announced a new set of guidelines for power-supply manufacturers. The guidelines, Version 2.0 of Intel's ATX12V Power Supply Design Guide, spell out physical form factor, cooling requirements, connector configuration, and electrical and signal-timing information.

The main portion of the spec calls for a minimum measured efficiency of 70% at full (100%) or typical (around 50%) load and 60% efficiency at light (20%) load. The guidelines recognize that PCs waste a lot of power when performing less demanding tasks. For instance, there is no need for the power supply to generate maximum power for such light tasks as sending e-mail or creating documents. Tests by Intel researchers showed that some power supplies are less than 50% efficient when not being fully used. The inefficiency shows up as heat, which must be removed from enclosures by fans.

The increase in efficiency is projected to cut power wastage for an average PC by about 25% or 50 W. A typical desktop PC and CRT monitor consume upwards of 200 W. This translates into an estimated electrical savings of about $17/year for each PC.

Other changes include replacing the current 2 10 main power connector with a 2 12 connector to support the new 75-W PCI Express requirement.