MSI MAG A750GLS PCIE5 ATX v3.1 PSU Review

Protection Features

OCP (Normal @ 30.4°C) 12V: 74.20A (118.72%), 11.988V
5V: 24.7A (137.22%), 5.068V
3.3V: 24.9A (138.33%), 3.302V
5VSB: 3.6A (144.00%), 4.96V
OCP (Hot @ 41.6°C) 12V: 71.50A (114.40%), 11.982V
5V: 24.9A (138.33%), 5.067V
3.3V: 24.9A (138.33%), 3.303V
5VSB: 3.5A (140.00%), 4.967V
OPP (Normal @ 30.0°C) 979.05W (130.54%)
OPP (Hot @ 41.0°C) 917.16W (122.29%)
OTP ✓ (105°C @ Secondary Side)
SCP 12V to Earth: ✓
5V to Earth: ✓
3.3V to Earth: ✓
5VSB to Earth: ✓
-12V to Earth: ✓
PWR_OK Proper Operation
UVP (Full Load @ 90V)
UVP (No Damage @ 80V)
Conducted Emissions EN55032 & CISPR 32A
NLO
Fan Failure Protection
SIP Surge: MOV
Inrush: NTC & Bypass Relay

The 12V rail’s OCP triggering points are set conservatively, and there is a satisfactory difference between normal and hot modes. On the other hand, the OCP triggering points are set high on the minor rails, and to make things worse, the triggering points are identical between normal and hot conditions. This is not good because the PSU is stressed way more under high operating conditions.

The over power protection is set correctly, and all other essential protection features, except for fan failure, are present.

EMC Pre-Compliance at a Glance

Every electronics device, including PSUs, can be an EMI source, which, depending on the amount of EMI emitted, can affect the proper operation of nearby devices. EMI can, in some extreme cases, even render them unusable. Some standards have been established to minimize electromagnetic interference (EMI) noise. The corresponding standards for IT (Information Technology) products are CISPR 32 and its derivativeEN 55032, which applies to products sold in the EU. In the EU, every product bearing the “CE” marking must comply with the EN 55032 standard. CISPR 32 and EN 55032 standards categorize devices into two classes: A and B. Class B equipment is intended for domestic environments. Hence, its permitted EMI emissions are significantly lower than those of A-class devices.

Our equipment for EMI readings:

  • Rohde & Schwarz FPC1500 (loaded with all options)
  • Tekbox TBLC08 LISN
  • Tekbox TBFL1 transient limiter
  • Tekbox EMCview software
CISPR 32 / EN55032 Limits
CISRP 32 / EN 55032 Class A Conducted EMI Limit
Frequency of Emission (MHz) Conducted Limit (dBuV)
Quasi-peak Average
0.15 – 0.50 79 66
0.50 – 30.0 73 60
CISPR 32 / EN 55032 Class B Conducted EMI Limit
Frequency of Emission (MHz) Conducted Limit (dBuV)
Quasi-peak Average
0.15 – 0.50 66 – 56 56 – 46
0.50 – 5.00 56 46
5.00 – 30.00 60 50
CISRP 32 / EN 55032 Class A 10-Meter Radiated EMI Limit
Frequency of Emission (MHz) Field Strength Limit (dBuV/m)
30 – 88 39
88 – 216 43.5
216 – 960 46.5
> 960 49.5
CISRP 32 / EN 55032 Class B 3-Meter Radiated EMI Limit
Frequency of Emission (MHz) Field Strength Limit (dBuV/m)
30 – 88 40
88 – 216 43.5
216 – 960 46.0
> 960 54.0

Please note that the ATX spec allows a 4 dB margin for conducted and radiated emissions. This means that if a PSU exceeds the limits but stays within the 4 dB margin, it meets the corresponding ATX spec requirement (8.1 Emissions).

EMI Results

In the samples I got, conducted EMI emissions were extremely high at low frequencies. The transient filter needs fixing ASAP.

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4 thoughts on “MSI MAG A750GLS PCIE5 ATX v3.1 PSU Review

  1. Yello, I’m in India and only have two same priced PSU options: MSI MAG A750GL and Deepcool PN750M, everything else is priced at 1.5 to 2 times these psu. They are almost identical units, but I’m still confused which to get. Which would you suggest?

    THANKS! 😁

      1. Hi Aris, quick clarification, when I asked about the MSI A750GL vs PN750M (under the GLS review), did you mean the GL or the GLS model in your reply? I only have the GL variant available.

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