From the outside…<\/h2>\n
The MSI MPG A850G power supply, despite its high wattage (850 W), has a relatively short chassis, which does not outgrow the shortest ATX power supplies too much. At 150 mm, this PSU is only 10 mm longer. At the same time, it already uses an extra-large 135 mm fan, which, compared to variants with proportionally smaller size (typically 120 mm), ensures higher airflow at comparable noise level, thus it is characterized by higher cooling efficiency.<\/p>\n
The grille in front of the fan could probably be more aerodynamic than it is, but even so, it won’t increase noise as significantly as designs with a traditional hexagonal pattern. And it obstructs the airflow less for the larger open area for sure.<\/p>\n
In terms of the basic efficiency categorization, it is “only” an 80 Plus Gold certified model, but within the ATX 3.0 standard, higher efficiency is already required<\/a>. Especially at very low load, where many users spend a significant amount of time. These are typically web browsing, light office work or video watching situations. These power supplies (versus ATX 2.x) also need to be better prepared for the higher current spikes that occur with today’s hardware. The A850G power supply should handle peak loads of up to 141.6 A on the 12V branch for 100 \u00b5s, double the claimed continuous (70.8 A) current load. You will find out if the power supply meets these specifications in the tests.<\/p>\n The higher current peaks are mainly due to graphics cards, for which ATX 3.0 power supplies also have a native 16-pin connector (12VHPWR). This is used so far only by more powerful graphics cards (from RTX 4070 Ti upwards) with Nvidia Ada Lovelace GPUs. This connector has all the parameters to be eligible for loads up to 600W, i.e. also for the GeForce RTX 4090. Its wires have a large cross-section \u2013 16 AWG (1.31 mm2<\/sup>), which will result in lower temperature at the same current than on connectors with a smaller cross-section. For external power supply of graphics cards, however, there is 16 AWG everywhere, even on 6+2-pins.<\/p>\n Smaller cross-section of wires (18 AWG) is on CPU power supply cables (but you can connect two of them on boards where you run a powerful processor and thus reduce temps) and on SATA\/Molex cables, for which there are always very low currents. In these cables, although there is only one wire per branch, 18 AWG is still enough \u2013 it’s still an above-average cross-section.<\/p>\n Owners of Radeons or older graphics cards (other than GeForce RTX 4000) may also be interested in the ability to use the 12VHPWR connector to connect two 6+2-pin PCIe connectors. There are then up to six of these in total, four of which are native connectors. Most of the cables are flat, the only exception being cables with 12VHPWR connectors.<\/p>\n The use of a 135 mm fan has already been mentioned, but it should be added that this is a 2300-rpm model with a powerful motor (0.5 A) and liquid bearings. According to MSI’s internal chart, high speeds should never be reached. At 100-percent load, the speed is supposed to end just above 1400 rpm. Meanwhile, up until 40% load (i.e. up to 340W), passive operation is promised in the case of the active Zero Fan mode (which is activated by a button on the rear, near the power switch). Otherwise, outside of semi-passive mode, the fan always runs, although up to half load its speed should be constant at about 460 rpm.<\/p>\n On the primary part, where the DC current comes in, there is a large, 400 V capacitor with a capacitance of 680 \u03bcF. This is a Nippon Chemi-Con (KMR) “105-degree” model with a low ESR number, which is a sort of quality index (the lower the number, the better). We will not argue about the (in)qualities of the design. Apart from the fact that we do not have adequate experience or the necessary qualifications for this, all that matters will eventually be revealed by the measurements of the electrical quantities, which are a perfect mirror of the qualitative characteristics of the components used.<\/p>\n For a basic overview, it is also worth mentioning that the smaller capacitors behind the main transformer (i.e. on the secondary part to regulate the voltage on the individual branches) are Nichicons. These are also among the best things to put in computer power supplies.<\/p>\n![\"\"](\"https:\/\/www.hwcooling.net\/wp-content\/uploads\/2023\/04\/msi-mpg-a850g_01.gif\")
<\/a><\/p>\n<\/a>\u00a0 \u00a0<\/a><\/p>\n<\/a>\u00a0 \u00a0<\/a><\/p>\n… and from the inside<\/h2>\n
<\/a><\/p>\n<\/a><\/p>\n
![in the header photo<\/a>) on the voltage regulators of the converters are also worth praising.<\/p>\n<\/div><\/th><\/th><\/th><\/th><\/th><\/th><\/th><\/th><\/th><\/th><\/th><\/th><\/th><\/tr><\/thead>Brand and model of the PSU <\/td>Basic parameters from the manufacturer <\/td><\/td><\/td><\/td><\/td><\/td><\/td><\/td><\/td><\/td><\/td>Price [eur] <\/td><\/tr><\/td>Continuous power output [W] <\/td>Continuous current load [A] <\/td><\/td><\/td>80 Plus <\/td>Connectors <\/td><\/td><\/td><\/td><\/td>AWG <\/td><\/td><\/tr><\/td><\/td>+12 V <\/td>+5 V <\/td>+3.3 V <\/td><\/td>16-pin * <\/td>6+2-pin * <\/td>8\/4+4-pin <\/td>SATA <\/td>4-pin Molex <\/td>18\u201316 <\/td><\/td><\/tr>MSI MPG A850G <\/td>850 <\/td>70.8 <\/td>22.0 <\/td>22.0 <\/td>Gold <\/td>1+0\u00d7 <\/td>4+2\u00d7 <\/td>2\u00d7 <\/td>7\u00d7 <\/td>4\u00d7 <\/td>18\u201316 <\/td>169 <\/td><\/tr><\/tbody><\/table><\/div>Wordpress Table Plugin<\/a><\/p>\n* We report the number of PCI Express connectors as the sum of native and shared ones (the second number after the “+” sign). Native connectors are those that are the same on both sides. Shared ones are then connected via different connectors on the power supply side, for example, a single 300-watt 16-pin (12VHPWR) is formed by using two 6+2-pin connectors, and vice versa \u2013 a 16-pin connector can be used to connect a cable with two 6+2-pin connectors.<\/strong><\/h6>\nImportant to note:<\/strong> Power supplies are and will continue to be a marginal topic for us, so don’t expect us to go into as much detail about them as we do with other components. The goal, of course, is to be able to choose your favourite based on the basic characteristics. Efficiency at different load levels, the effect of electrical power on voltage drop or its output ripple, we will map it all out. And perhaps, if there is interest, we will also devote space to a frequency analysis of the sound of the coils. But you’ll have to wait a while for the results of any tests.<\/div>\nEnglish translation and edit by Jozef Dud\u00e1\u0161<\/em><\/p>\n](\"https:\/\/www.hwcooling.net\/wp-content\/uploads\/2023\/04\/msi-mpg-a850g-01.gif\"){kind=link}