Comparison be quiet! Straight Power 11 Platinum BN307 vs be quiet! Straight Power 11 BN283

Efficiency, in this case — the ratio of the power of the power supply (see "Power") to its power consumption. The higher the efficiency, the more efficient the power supply, the less energy it consumes from the network at the same output power, and the cheaper it is to operate. Efficiency may differ depending on the load; the characteristics can indicate both the minimum efficiency and its value at an average load (50%).

It should be noted that compliance with one or another level of 80PLUS efficiency directly depends on this indicator (for more details, see "Certificate").

The presence or absence of an 80+ certificate for the power supply. This certificate indicates high energy efficiency: to obtain it, the efficiency (see above) must be at least 80%, and in different modes (20%, 50% and 100% of the maximum load). There are several degrees of 80+:

— 80+. The original version of the certificate, assuming an efficiency of at least 82% (at least 85% for 50% load).

— 80+ White. The second name of the original 80+ certificate (see above).

— 80+ Bronze — efficiency not less than 85% (for half load — 88%).

— 80+ Silver — respectively 87% (90% for half load).

— 80+ Gold — 89% (92% for half load)

— 80+ Platinum — 90% (94% for half load).

— 80+ Titanium — 94% (96% for half load).

The power factor (see "PFC Type") must be at least 0.9 for the lower levels and at least 0.95 for the Platinum level. Also note that for redundant power used in server systems, the efficiency requirements are somewhat lower.

A standard for power supplies that supplements the ATX specifications regarding power supply along the 12 V line. Introduced into use since the time of the Intel Pentium 4 processor. In the first series of the standard, the +5 V line was mainly used; from version 2.0, the +12 V line was introduced to fully power the components computer. Also in the second generation, a 24-pin power connector appeared, used in most modern motherboards.

The presence of at least one Floppy power connector in the PSU.

Initially, this connector was intended to power floppy disk drives, hence the name. It is also known under the designation "mini-Molex". Anyway, this standard is generally considered obsolete, but it is still used by some specific types of components, and therefore continues to be used in power supplies.

The maximum current that the PSU is capable of issuing to the power line is -12V.

For more information about power lines in general, see "+3.3V". Here it is worth mentioning that 12 V is the most popular voltage among computer power connectors. However, most often it is used in the + 12V format; and the -12V line performs mainly a service function, it is almost never found in other connectors, except for the motherboard power plug (for 20 or 24 pins).

The maximum power that the PSU can deliver to the +12V power rail.

For more details on power rails in general, see "Maximum current and power." Here, it should be noted that 12V is the most popular voltage among computer power connectors. It is used in nearly all such connectors (with few exceptions), and some plugs (such as the additional PCI-E power for 6 or 8 connectors) use only 12-volt rails, specifically in the +12V format. Therefore, this indicator is one of the most important characteristics of any PSU.

It is worth noting that many PSUs have multiple separate +12V power rails. In such cases, the total power is indicated here, which is usually divided equally among the rails.

The maximum power that the PSU is capable of delivering on the + 3.3V and + 5V power lines.

See "Maximum current and power" for details on power lines in general. Here we note that the power lines + 3.3V and + 5V are used both in the general connector for the motherboard (for 20 or 24 pins), and in specialized plugs — in particular, the SATA power connector (both) and Molex (only +5V, in addition to +12V). The power of these lines is a rather specific parameter, rarely required in fact; it is usually the same for both voltages, so it is indicated in the general clause.

Protection schemes provided in the power supply unit. In addition to the aforementioned OVP (Over Voltage Protection), OPP (Over Power Protection), and SCP (Short Circuit Protection), modern PSUs may include the following safety functions:

— OCP. OCP in power supplies monitors the current on power lines and shuts down the PSU if consumption becomes dangerously high, to prevent overheating wires, connectors, and power elements inside the unit, and to avoid affecting components. Unlike OPP, which triggers based on the total power of the whole unit, OCP often catches a localized issue on a specific line or group of outputs. Compared to SCP, it's an "earlier" protection: it reacts before a full short circuit forms when resistance is not zero but current is already risky. Real-life examples include an unsuccessful graphics card overclock, a damaged GPU power cable, or the rare but unpleasant case of connector bending/melting: OCP will shut down the unit faster than you'll notice the smell of plastic.

— UVP. UVP monitors the voltage drop on the power supply's outputs and shuts it down when the values become too low for stable operation to avoid freezes, data writing errors, and "half-dead" modes, which are especially unpleasant for the motherboard and drives. Paired with OVP, these protections work like "frames": OVP catches dangerous spikes, UVP catches dangerous drops, while SIP often tries to smooth out the power issue at the input. A typical ex...ample would be an overloaded weak PSU, poor grid, or turning on powerful appliances at home: instead of unstable operation and strange reboots, UVP prefers to shut down the system predictably.

— OTP. OTP monitors the temperature inside the power supply and shuts it down when the heat becomes critical, protecting the transformer, power switches, and capacitors from accelerated wear and accidents. This is a "harsher" safety net than AFC: automatic fan control tries to prevent overheating, while OTP kicks in when cooling no longer suffices— for example, if the case is clogged with dust, the fan stops, the PSU is in a cramped compartment, or the PC runs under heavy load for a long time in summer. In real life, OTP often saves the day when a user inadvertently blocks the air intake or the fan starts failing: instead of smoke and component degradation, the unit simply turns off.

— SIP. SIP in power supplies is designed for "dirty" power conditions: transient surges, drops, and inrush currents that occur when a fridge compressor, pump, or air conditioner starts up at home, or when the network is unstable. Conceptually, it aligns closer to smoothing out input problems than to OVP/UVP, which already monitor the output and simply shut down the PSU at dangerous values; SIP aims to enhance system resilience to everyday voltage drops and spikes but does not replace a full external stabilizer or robust power protection if the grid is truly bad. A typical example would be a private house or old housing stock: SIP helps endure minor network "nudges" without sudden reboots.

— NLO (No-Load Operation). The ability of a power supply to correctly start and operate even with zero or very low load on the outputs, without "floating" voltages and instability. Unlike protections like OVP/OCP/SCP that respond to emergencies (overvoltage, overload, short circuit) and often shut down the PSU, NLO focuses on stability when consumption is minimal, or the load is temporarily absent, reducing the risk of odd malfunctions during testing or in energy-saving scenarios. In practice, NLO is useful when testing the unit on a bench without a connected PC, when the system starts with a minimal set of components, and when the computer spends most of the time idling, reducing consumption to a "trivial" level.

— AFC. AFC in power supplies manages fan speed based on temperature and load: it rotates slower and quieter when idle, and speeds up as consumption increases to dissipate heat in time. This is not "emergency" protection like OTP, which shuts down the unit during overheating, but a preventative measure: AFC helps maintain temperature at a normal level, thereby indirectly prolonging the lifespan of PSU components. A real-life example is that at night, in a quiet room, the PC doesn't hum under low load, and during gaming, the cooling automatically intensifies, preventing OTP from triggering.

PC PSU dimensions are defined by the form factor (most often ATX 150×86 mm), and the key factor in compatibility is depth — the PSU case length. “Universal” ATX units are usually 140, 150 mm, while quiet, high-power models with large heatsinks and a 135/140‑mm fan range from 160 to 200+ mm; compact builds use SFX/SFX-L (depth ~100 and ~125 mm with an adapter bracket). The greater the depth, the higher the risk of hitting drive cages, the PSU shroud, cable management, or a front LCS radiator, and modular connectors plus cable bend radius require another 20 – 40 mm of real clearance.