Be quiet!, a leading supplier of power supply units from Europe, said this week that all of its power supply units (PSUs) available on the market today, are compatible with Intel Corp.’s next-generation Core i-series “Haswell” microprocessors. The company also revealed some information about its previous-generation products that are currently in use by its customers.
It recently transpired that Intel Haswell's C6/C7 power states require a minimum load of 0.05A on the 12V2 rail, whereas many desktop PSUs just cannot provide that low current. Numerous older PSUs, which comply with ATX12V v2.3 design guidelines that only called for a minimum load of 0.5A on the CPU power rail, can be equipped with a less sophisticated internal feedback loop/protection that cannot supply 0.05A to CPU. As a result, unless C6/C7 power states are disabled in the BIOS, PCs with older/cheap PSUs may become unstable when processors enter these states. To make the matters worse, many power supply units do not report minimum currents supported by 12V2 rail. As a result, it is now hard for system makers and end-users to determine whether their PSUs are Intel Core i-series “Haswell” compatible.
All current power supply models from Be quiet!, starting with the entry-level Pure Power L8 up to the high-end Dark Power Pro 10, are able to deliver the above mentioned low loads without problems. Even older models are mostly compatible with the fourth-generation Intel Core i microprocessors. Dark Power Pro 10 (all models), Straight Power E9 (all models), Pure Power L8 (all models), System Power 7 (all models) and Pure Power L7 (630W and 730W) are fully Haswell compatible.