SAMA P1000 ATX 3.1 PSU Review – 1kW platinum power at a competitive price

1 - Introduction and technical data 2 - Unboxing, asccessory and cables 3 - Teardown, components, fan and protection circuits 4 - Cybenetics methods and equipment 5 - Performance and test results 6 - Operating noise 7 - Efficiency and power consumption 8 - Summary and conclusion

Internal structure and components

The internal structure of the SAMA P1000 shows a clearly structured and functionally oriented platform, which is typical for RSY and focuses on efficiency, solid thermal reserves and cost-efficient component selection. The architecture corresponds to a modern LLC resonant platform with active PFC and downstream DC-DC modules. This is now standard in the medium to high power range, as this topology enables both good efficiency values and smooth control behavior. The design looks tidy, the components are logically arranged and the soldering quality is at a clean level, which ensures a reliable electrical connection and low thermal load.

In the input area you can see the complete EMI filtering with X and Y capacitors, common-mode chokes and a MOV element that absorbs voltage peaks. The inrush current is limited by an NTC thermistor, which works in combination with a relay that removes the resistor from the circuit after start-up. This solution minimizes the power loss during operation and in practice is significantly more durable than pure NTC approaches of older platforms.

The APFC stage of the power supply unit uses three Maple Semi SLF65R170E7 MOSFETs and an MSP06065G1 boost diode. RSY relies on manufacturers that offer a good balance between efficiency, thermal load capacity and price. Two 420 V capacitors with 390 µF each from the Nippon Chemi-Con KMR series are used as energy storage devices, which are specified for 105 °C and can therefore be expected to have a long service life. The total buffering of 780 µF is appropriate for a 1000 W device and explains, among other things, the measured hold-up time of 21 ms, which is within the usual range for comparable devices.

RSY uses four Convert CS20N50FF MOSFETs for the main conversion, which operate in a half-bridge LLC resonant converter. The combination of LLC topology and these MOSFETs results in high efficiency in the medium and upper load range, which is confirmed by the measured efficiency values. This stage is controlled by a Texas Instruments UCC25600, while the APFC controller UCC28180 also comes from the same company. Both controllers are considered established and reliable, which is why they are often found in power supply units in this power class.

The secondary side is based on synchronous rectification for the 12 V rail, which results in both efficiency gains and a lower thermal load compared to classic diode solutions. The 5 V and 3.3 V rails are produced using DC-DC converters, which are located on their own small daughter boards. These modules are responsible for stable output voltages with changing loads and contribute to the very good measured values for load regulation, which Cybenetics has confirmed with a maximum deviation of 1.17 %. Electrolytic capacitors from various Taiwanese manufacturers are used in the secondary circuits, which are supplemented by a large number of polymer capacitors. This mixed concept supports both high ripple robustness and good thermal behavior under continuous load.

A striking feature is the wide heat sink in the transformer area, which provides a large surface area for waste heat dissipation. Together with the 140 mm FDB fan, this results in a well-calculated thermal concept, which explains the quiet operation and low temperatures, which are visible in the LAMBDA-A certification of only around 19.6 dB(A). The coils are cleanly fixed, which reduces mechanical whining, and the transformer itself is also potted, so that vibrations are dampened. The 12V 2×6 connection area is housed on a separate board that clearly separates signal lines and sense pins, which complies with ATX 3.1 specifications and increases electrical safety.

The entire internal structure shows that RSY uses a well thought-out, modernized mid-range platform that forms a reliable basis with high-quality primary capacitors, solid MOSFET assembly and efficient design. Even if individual components such as secondary electrolytic capacitors do not come from the absolute premium segment, the combination results in a technically balanced mix that plausibly reflects the measured efficiency and ripple values and thus supports the power supply’s claim in its price category. Overall, the impression is of a robust and functionally high-quality implementation that does without unnecessary cost drivers and still fulfills the decisive performance features of modern systems.

Fan

The fan used in the SAMA P1000 comes from Globe Fan and bears the model designation S1402512HH, a 140 mm FDB fan with a rated voltage of 12 volts and a current consumption of 0.50 amps. globe Fan has been an established supplier to the power supply industry for many years and is frequently used in mid-range and high-end platforms because the company relies on robust bearing technology and reliable manufacturing. The decision to use a 140 mm fan is already a clear indication that RSY has chosen a design that is geared towards low noise levels and an even thermal load. Larger fans can rotate more slowly with the same air flow, which significantly reduces the noise level and at the same time increases the cooling reserve.

The Fluid Dynamic Bearing (FDB) used is one of the higher quality bearing types in the power supply sector. This bearing uses a hydrodynamically stabilized oil film that guides the rotor almost friction-free and significantly improves both running smoothness and service life. FDB bearings are particularly advantageous in situations with high thermal loads because they are not prone to rapid wear and, unlike plain bearings, remain stable even when mounted vertically for long periods. This makes the fan well suited for systems that run continuously with higher loads or are operated in warm environments. The operating expectancy of such a bearing is clearly longer than the service life of simpler bearing technologies such as sleeve or rifle bearings, which has a positive effect on the reliability of the entire power supply unit.

A look at the rotor blade design shows an aerodynamically optimized shape that is designed for the most efficient airflow possible with low turbulence. The wide blades generate sufficient static pressure to reliably flow through the internal cooling structure of the power supply unit. At the same time, the asymmetrical strut behind the rotor reduces resonance and thus minimizes tonal noise. This combination explains why Cybenetics measurements have shown an extremely low noise level during operation, leading to LAMBDA-A certification with an average of only around 19.6 dB(A).

The embedding of the fan in the power supply housing is also well thought out. The grille has an open, large-area structure that avoids air resistance and enables the fan to generate sufficient volume flow at low speed. The positioning of the fan is based on the main heat sources of the device, in particular the transformer, the MOSFETs on the primary side and the rectifiers on the secondary side. The design of the airflow ensures that the waste heat is dissipated evenly without creating hotspots that would provoke additional fan acceleration.

In practice, this combination of fan selection, bearing technology and housing opening results in very quiet operating behavior that is clearly above the mid-range market standard. While many power supply units in the same price range rely on smaller or technically simpler fans, the SAMA P1000 uses a solution that is acoustically and thermally at the top end of its class. Even if premium manufacturers occasionally use even higher quality motors or particularly decoupled mounting systems, the performance of this Globe FDB model remains remarkably strong in the context of the price and the target group.

Protective circuits

The protective circuits of the SAMA P1000 form a central element for operational safety and serve to protect the power supply unit, the connected hardware and, in a broader sense, the user from electrical faults. RSY relies on a complete set of modern protection mechanisms that cover both the primary and secondary sides and are based on the specifications of the ATX 3.1 standard. Firstly, there is the overcurrent protection (OCP), which is active on all relevant rails. This function monitors the maximum permissible current flow and disconnects the output as soon as excessive current consumption is detected. OCP is particularly essential for the 12 V rail, which carries almost the entire output power in this power supply unit, as it can determine the entire load characteristics of a modern system in the event of a fault. The measured values from the protocol show that the OCP thresholds have been dimensioned in line with practical requirements. They allow short load peaks without provoking an unintentional shutdown, but intervene reliably as soon as the critical range is exceeded.

Overvoltage and undervoltage protection (OVP/UVP) is also a must for a power supply unit in this class. OVP ensures that the outputs do not rise above their standard values in the event of faulty regulation, defective components or uncontrolled oscillations. UVP, in turn, prevents rails from falling below excessively low voltages, which could destabilize or damage digital components in particular. Together, both protection mechanisms ensure that the voltage stability remains within the defined limits, which further underpins the low load deviation documented in the Cybenetics measurements. The overload protection (OPP) is another important feature, as it protects the power supply unit from thermal or electrical overload in the event of an overload. The OPP of the SAMA P1000 is documented in the test protocol with practical response points. It allows a certain overload reserve, as is typical with short-term load jumps of modern graphics cards, but triggers early enough not to jeopardize the main switching stage. This is particularly relevant in the context of ATX 3.1 because the standard allows high transients, which can quickly lead a power supply into areas that would be critical without OPP.

The overtemperature protection (OTP) works independently of the fan control and switches the device off in the event of a thermal emergency. This takes effect, for example, if the air flow is obstructed or if the fan is not cooling sufficiently. RSY relies on several temperature sensors in areas of high thermal load such as the PFC stage and transformer. The interaction of OTP and OPP ensures that the power supply unit does not suffer any consequential damage in the event of a technical or environmental overload, even if the fan alone can no longer compensate for the temperature rise. Short circuit protection (SCP) is the basic safety function that triggers an immediate shutdown of the affected rail or the entire device if a circuit collapses completely due to a hard short. The SCP takes effect quickly and reliably in the SAMA model, which is particularly important in the scenario of a damaged cable or a defective peripheral device.

The supplementary protection mechanisms include the inrush current limiter, which is implemented via an NTC thermistor and a relay. This combination prevents excessive inrush currents and thus increases both the mains compatibility and the life expectancy of the primary components. In addition, the device has surge protection against mains peaks, which works through the interaction of MOV and EMC filter. One point where the platform falls slightly behind some premium manufacturers is the lack of fan failure protection. This protective function would detect if the fan stops or does not start up correctly and switch off the power supply in this case. Although the OTP can intercept such scenarios indirectly, because a thermal emergency inevitably leads to intervention, direct detection of the fan failure would be a desirable addition, which is seen more frequently in higher-quality power supply units.

This results in a fairly coherent picture; the protection circuits of the SAMA P1000 cover all practical areas and correspond to what can be expected in this performance class and price structure. The response points are sensibly selected and match the electrical characteristics of the platform, ensuring reliable operation even under demanding load patterns.