tricks with increasing / cases, power supply and cooling

tricks with increasing / cases, power supply and cooling

The fanless PSUs in the Seasonic product line are represented by 450, 500, 600 and 700 W models – all of which belong to the flagship PRIME series. Note that the belonging of the power supply to this series not only flatters the feeling of its own greatness, but also provides such a model with the longest warranty period (12 years).

We are already familiar with the oldest of these models – Seasonic PRIME Fanless TX-700. A record output power for a model with passive cooling and an equally outstanding warranty period are combined with a very large size of the power supply unit (170 mm in length) and a very high price ($ 260 in the USA and about 25 thousand rubles in Russia). The PRIME 600 Titanium Fanless power supply unit as a whole differs from this model only in lower output power and nuances of the cable system and equipment.

We will examine the capabilities of the younger representatives of the PRIME Fanless line with a lower output power and certification at the level of 80 PLUS Platinum now, but looking ahead, we can note their standard sizes for ATX power supplies and a noticeably more attractive cost (including less overpayment in comparison with overseas price tag).

⇡ #Packaging, delivery set, appearance

The packaging with its glossy shine repeats the features already familiar to us from the Seasonic PRIME series models, but the box has a more modest size.

The design is quite traditional for any Seasonic models. The front of the box bears the name of the manufacturer and model, the 80 PLUS Platinum certification logo, as well as references to a fully modular cabling system, a fanless design and a 12-year manufacturer’s warranty.

On one end of the box there is a table with electrical parameters, a list of available cables and connectors, and logos of certificates of conformity that the power supply meets. On the other side of the package, as a whole, the information from the “facade” is repeated and there is a photograph of the power supply.

The back of the box traditionally offers an extended description of the model’s features, which is supplemented by an efficiency diagram for 115 and 230 V power grids and a photograph of the device.

The package includes a multilingual printed manual, a booklet urging to register a product with a chance to win $ 50 to buy games on Steam, a tester to check the power supply without installing it into a case, and a set of fasteners supplemented with disposable and reusable cable ties.

The power supply is packed in a beautiful velvet pouch, and the cables from the kit are placed in simple plastic bags. Instead of the usual bag made of non-woven material for storing them, there is only the already familiar leaflet with the notice of the removal of such materials from the delivery set, since they are required for the manufacture of medical masks.

The only difference that we were able to identify between the two power supplies under consideration is the organization of the cable system. The 500 W model has a second cable for additional power supply to the processor and, accordingly, a connector for it on the front panel.

Otherwise, as far as we can tell, the blocks are completely identical: they have the same number and capacity of the soldered capacitors, as well as the number of power elements (although there may be differences in their ratings). Therefore, we will continue to study the exterior and internal structure only according to a more powerful model in a pair – although we will measure voltage stability, efficiency and ripple level for both blocks.

The power supply has a standard dimensions of 140 × 150 × 86 mm, which allows it to be placed in any ATX case. At the same time, even a quick glance at the internal structure through the lattice sides and the lid allows you to understand that the younger representatives of the PRIME Fanless series are based on the FOCUS platform, and not PRIME.

External differences from FOCUS models with active cooling are reduced to a fundamentally different case cover, covered on all sides with ventilation holes (the shape of which is in the form of elongated hexagons, however, is borrowed from the traditional design of the PRIME series blocks).

The cable connection panel has fewer connectors than active cooling FOCUS units due to the lower power output of the fanless models.

The back panel is covered with a ventilation grill. It houses the power cord inlet and the device switch. On the bottom of the case is a sticker with information about the model, including the input and output electrical parameters.

⇡ #Specifications

Manufacturer Seasonic
Model PRIME Fanless PX-500 PRIME Fanless PX-450
Model index SSR-500PL SSR-450PL
Connecting cables Fully modular Fully modular
Maximum load power, W 500 450
80 PLUS Certification Platinum Platinum
ATX version ATX12V 2.4 ATX12V 2.4
Power grid parameters 100-240 V, 8-4 A, 50-60 Hz 100-240 V, 7-4 A, 50-60 Hz
Efficiency > 92% > 92%
PFC Active Active
Load protection OVP (over voltage protection) OVP (over voltage protection)
OPP (over power protection) OPP (over power protection)
OCP (over current protection) OCP (over current protection)
UVP (undervoltage protection) UVP (undervoltage protection)
OTP (over temperature protection) OTP (over temperature protection)
SCP (short circuit protection) SCP (short circuit protection)
Dimensions, mm 140 × 150 × 86 140 × 150 × 86
Weight, kg ND ND
Mean time between failures (MTBF), h 150,000 at 25 ° C 150,000 at 25 ° C
Warranty period, years 12 12
Estimated retail price, RUB 14,500 13,000

The electrical data table located on the bottom of the power supply indicates that 492of the 500 W total output power of the PX-500 model, it can be directed at 12 V. The permissible total load on the 3.3 and 5 V lines is 100 W, which is more than enough for any modern system. The standby power supply allows a load of up to 2.5 A.

The less powerful PX-450 differs only in lower total output power and permissible load on the 12V line (450 and 444 W, respectively).

The units are guaranteed to operate continuously at 100% output power at ambient temperatures from 0 to 40 ° C and at 80% power at 40 to 50 ° C. At the same time, the MTBF is an impressive 150 thousand hours (at an ambient temperature of 25 ° C).

The efficiency ratings of the PSUs in question are 80 PLUS Platinum. The manufacturer’s warranty is 12 years – the most generous offer on the market.

⇡ #Cables

The cabling system is well suited to modern requirements for the range of available connectors, especially given the relatively modest power output. The distance between the connectors on SATA and Molex cables is 10 cm. The total cable lengths are shown below.

The PX-500 Connector / Cable Kit includes:

  • 1 × 20 + 4 pins (61 cm);
  • 2 × ATX12V (4 + 4 pins) – CPU power supply (65 cm);
  • 2 × 6 + 2 pins – additional power supply for PCIe cards (75 cm);
  • 8 × SATA (81 and 86 cm);
  • 3 × Molex (69 cm);
  • 1 × Molex to SATA adapter (30 cm).

The PX-450 model differs only in the absence of a second cable for powering the CPU.

The main power cable with 20 + 4-pin connector is nylon braided, all other cables are in a flat design.

Traditionally for Seasonic, the cross-section of all wires is typical 18 AWG – there are no attempts either to save on wires with low load, or to strengthen the most loaded CPU and PCI-E power cables.

⇡ #Construction, internal structure

Looking inside, the Seasonic FOCUS platform is unmistakably recognizable, taken without major changes (the older PRIME Fanless TX-700 differed from the original FOCUSversion of the DC-DC converter).

Accordingly, like most modern high-efficiency power supplies in general, the considered power supplies are based on a half-bridge resonant conversion topology.

A clear difference from the “active” FOCUS models are only much larger cooling radiators, which have radically increased the dissipation area.

A small aluminum plate between the boards with modular connectors and DC-DC converters has acquired a spreading ribbed superstructure.

In the area where solid-state output capacitors are located, rudimentary aluminum plates without ribbing were supplemented by a pair of rather large radiators (can be compared with a similar position on conventional “tricks”).

Only two small radiators with power elements in the central part of the main board were not added in size – but they initially have a fairly well-developed fins.

The configuration of the input filter is expectedly the same as that of the power supplies on the FOCUS platform: at the input of the power cord there is a capacitor CX and a pair of capacitors CY, and on the main PCB there is the same set of capacitors, two common mode chokes, a varistor and a fuse.

The input capacitor from Nippon Chemi-con has a capacitance of 390 μF.

Capacitor the same capacity is used on the 450 watt model.

The output electrolytic capacitors are Japanese made by Nichicon and Nippon Chemi-con.

The only control microcircuit on the upper side of the main PCB is the Excelliance MOS 8569C standby power controller – which is already familiar from the rest of the FOCUS platform.

There are smoothing capacitors on the panel with modular connectors.

The general level of the used components and the build quality are traditionally for Seasonic at the highest level.

⇡ #Testing technique

The testing methodology adopted in 3DNews is described in a separate article, which is recommended for reading to understand the structure of computer power supplies and their most important characteristics. Refer to it to find out why it is needed and how this or that component mentioned in the review works, and how to interpret the test results.

⇡ #Test results

The efficiency of Seasonic PRIME Fanless PX-450 and PX-500 measured during testing turned out to be expectedly high (since the efficiency graphs of these models would practically merge, we made them separate).

In part, such high rates are a consequence of the measurement error of the household wattmeter, which underestimates the power “from the socket” at medium and heavy loads. In general, the recorded results are comparable to the results of other “platinum” models that have passed our tests.

The results of the 80 PLUS certification report will be closer to real values ​​of efficiency. At 10/20/50/100% capacity, the efficiency of Seasonic SSR-450PL was 86.07 / 90.87 / 92.65 / 91.12%, respectively, and the efficiency of Seasonic SSR-500PL was 85.49 / 90.34 / 92 , 37 / 90.85%. These results were obtained on a 115 V supply, so the efficiency should be slightly higher on a 230 V supply.

On the whole, the result is consistent with our measurements: the efficiency of a 450-watt unit turns out to be slightly (literally a fraction of a percent) higher.

Since the considered power supplies do not have fans, then, accordingly, there are no schedules for their operation. We can only note the absence of any extraneous overtones like the whistle of chokes during operation.

The cross-load characteristics of both units look absolutely perfect: the deviations of the main voltages at any load do not go beyond 1% of the nominal. More powerful Seasonic FOCUS units with active cooling, as a rule, “sagged” the 5 V line a little at maximum loads across all voltages, but this was not observed in the models under consideration due to the lower output power.

12V bus, high-frequency ripple of the PX-450 unit

12V bus, high-frequency ripple of the PX-450 unit

12V bus, low-frequency ripple of the PX-450 unit

12V bus, low-frequency ripple of the PX-450 unit

5 V bus, high-frequency ripple of the PX-450 unit

5 V bus, high-frequency ripple of the PX-450 unit

5 V bus, low-frequency ripple of the PX-450 unit

5 V bus, low-frequency ripple of the PX-450 unit

Seasonic PRIME Fanless PX-450 power supply shows the minimum level of ripple in all modes. The largest deviations are noticeable along the 12 V line at low frequencies, but their swing does not even reach 30 mV with an allowable 120 mV.

12V bus, high-frequency ripple of the PX-500 unit

12V bus, high-frequency ripple of the PX-500 unit

12V bus, low-frequency ripple of the PX-500 unit

12V bus, low-frequency ripple of the PX-500 unit

5 V bus, high-frequency ripple of the PX-500 unit

5 V bus, high-frequency ripple of the PX-500 unit

5 V bus, low-frequency ripple of the PX-500 unit

5 V bus, low-frequency ripple of the PX-500 unit

The voltage ripple of the more powerful PRIME Fanless PX-500 unit is slightly more pronounced. The ripple swing on the 12 V line is approaching 40 mV, and the deviations in other modes are also slightly higher. However, this block also meets the requirements of the standard with at least a threefold margin.


Both the considered passive power supplies showed almost ideal electrical parameters: perfect voltage stability, low ripple range and efficiency quite worthy of its certification level. The models also have a good set of supplies and a record-long warranty period.

The fact that these models of the flagship PRIME series are based on the platform used in the more affordable FOCUS series of power supplies cannot be attributed to disadvantages: the electrical parameters do not cause the slightest criticism, the smaller size is better suited for assembling systems in small cases, and the price tag at the same time, it is lower than that of representatives of the “real” PRIME platform. At the same time, the external design, delivery set and the warranty period of the considered models correspond exactly to the PRIME series, and not to FOCUS.

The difference between the 450- and 500-watt model is apparently reduced solely to the presence of the latter with a second 4 + 4-pin CPU power cable – which is not required by all users (especially if we are talking about compact low-noise systems that are not aimed at serious overclocking). The rest of the filling of the models, as far as we can judge, is completely the same.

At the time of preparation of the material, according to Yandex.Market, fanless power supplies in domestic retail were represented exclusively by Seasonic models, and it is the models with a capacity of 450 and 500 W that are most common in retail and are sold at a fairly adequate price: for the younger model, on average, they ask about 13 thousand rubles, and for the older one – 1,000-1,500 rubles more. Although this is higher than overseas price tags (on – $ 145 and $ 155, respectively), the overpayment is not as great as for more powerful models with the 80 PLUS Titanium certification, which in themselves are much more expensive.

If you notice an error, select it with the mouse and press CTRL + ENTER.

Leave a Comment