Comparison MSI MAG GN PCIE5 A750GN vs Deepcool PN-D PN750D

The bearing is the piece between the rotating axle of the fan and the fixed base that supports the axle and reduces friction. The following types of bearings are found in modern fans:

— Sliding. The action of these bearings is based on direct contact between two solid surfaces, carefully polished to reduce friction. Such devices are simple, reliable and durable, but their efficiency is quite low — rolling, and even more so the hydrodynamic and magnetic principle of operation, provide much less friction.

— Rolling. They are also called "ball bearings", since the "mediators" between the axis of rotation and the fixed base are balls (less often — cylindrical rollers) fixed in a special ring. When the axis rotates, such balls roll between it and the base, due to which the friction force is very low — noticeably lower than in plain bearings. On the other hand, the design turns out to be more expensive and complex, and in terms of reliability it is somewhat inferior to both the same plain bearings and more advanced hydrodynamic devices. Therefore, although rolling bearings are quite widespread nowadays, however, in general, they are much less common than the mentioned varieties.

— Hydrodynamic. Bearings of this type are filled with a special liquid; when rotated, it creates a layer on which the moving part of the bearing slides. In this way, direct contact between hard surfaces is avoided and friction is significantly reduced compared to previous...types. Also, these bearings are quiet and very reliable. Of their shortcomings, a relatively high cost can be noted, but in fact this moment often turns out to be invisible against the background of the price of the entire system. Therefore, this option is extremely popular nowadays, it can be found in cooling systems of all levels — from low-cost to advanced.

— Magnetic centering. Bearings based on the principle of magnetic levitation: the rotating axis is "suspended" in a magnetic field. Thus, it is possible (as in hydrodynamic ones) to avoid contact between solid surfaces and further reduce friction. Considered the most advanced type of bearings, they are reliable and quiet, but expensive.

The number of SATA power connectors provided in the PSU.

Nowadays, SATA is the standard interface for connecting internal hard drives, and it is also found in other types of drives (SSD, SSHD, etc.). Such an interface consists of a data connector connected to the motherboard, and a power connector connected to the PSU. Accordingly, in this paragraph we are talking about the number of SATA power plugs provided in the PSU. This number corresponds to the number of SATA drives that can be simultaneously powered from this model.

Number of 8-pin PCIe power connectors (6+2) provided in the PSU design.

Additional PCIe power connectors (of all formats) are used for additional power to types of internal peripherals that require more than the 75W supplied directly through the PCIe slot on the motherboard (a typical example is graphics cards). In PC components, there are two types of such connectors — 6-pin, providing up to 75W of additional power, and 8-pin, giving up to 150W. The 8-pin (6+2) connectors used in power supplies are universal: they can work with both 6-pin and 8-pin connectors on the expansion board. Therefore, this type of connector is the most popular in modern PSUs.

As for the quantity, there are models on sale with 1 PCIe 8-pin (6+2) connector, 2 such connectors, 3 connectors, 4 connectors, and in some cases — 6 or more. Several of these connectors can be useful, for example, when connecting multiple graphics cards — or for a powerful high-performance video adapter equipped with multiple additional PCIe power connectors.

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.

Manufacturer's warranty provided for this model.

In fact, this is the minimum service life promised by the manufacturer, subject to the rules of operation. There are both models with a small warranty up to 3 years, and more advanced power supplies, in which the warranty can reach 7, 10 years and even 12 years. In general , a 5-year warranty(for example) does not mean that the device will fail after the specified time. Most often, the actual service life of the device is much longer than the guaranteed one.

Specific warranty periods may vary even for similar drives from the same manufacturer. So not