Cooler Master MasterWatt Maker 1200 PSU Review

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Transient Response Tests

Advanced Transient Response Tests

For details on our transient response testing, please click here.

Ιn these tests, we monitor the PSU's response in two different scenarios. First, a transient load (10A at +12V, 5A at 5V, 5A at 3.3V and 0.5A at 5VSB) is applied for 200ms while the PSU works at 20 percent load. In the second scenario, the MasterWatt Maker 1200 is hit by the same transient load while operating at 50 percent load. In both tests, we use our oscilloscope to measure the voltage drops caused by the transient load. The voltages should remain within the ATX specification's regulation limits.

These tests are crucial because they simulate the transient loads a PSU is likely to handle (such as booting a RAID array or an instant 100 percent load of CPU/GPUs). We call these tests "Advanced Transient Response Tests," and they are designed to be very tough to master, especially for a PSU with a capacity of less than 500W.  

Advanced Transient Response at 20 Percent

Swipe to scroll horizontally
VoltageBeforeAfterChangePass/Fail
12V12.073V12.012V0.51%Pass
5V5.069V4.921V2.92%Pass
3.3V3.337V3.175V4.85%Pass
5VSB5.008V4.942V1.32%Pass

Advanced Transient Response at 50 Percent

Swipe to scroll horizontally
VoltageBeforeAfterChangePass/Fail
12V12.027V11.970V0.47%Pass
5V5.020V4.879V2.81%Pass
3.3V3.309V3.155V4.65%Pass
5VSB4.933V4.828V2.13%Pass

The +12V rail's response is amazing in these tests. We can't say the same for the other rails, though. The 3.3V rail's performance is especially disappointing.

Here are the oscilloscope screenshots we took during Advanced Transient Response Testing:

Transient Response At 20 Percent Load

Transient Response At 50 Percent Load

Turn-On Transient Tests

In the next set of tests, we measured the PSU's response in simpler transient load scenarios—during its power-on phase.

For the first measurement, we turned off the PSU, dialed in the maximum current the 5VSB could output, and switched the PSU on. In the second test, we dialed the maximum load the +12V could handle and started the PSU while it was in standby mode. In the last test, while the PSU was completely switched off (we cut the power or flipped the power supply's on/off switch), we dialed the maximum load the +12V rail could handle before switching the PSU on from the loader and restoring power. The ATX specification states that recorded spikes on all rails should not exceed 10 percent of their nominal values (+10 percent for 12V is 13.2V, and 5.5V for 5V).

We noticed a small voltage spike at 5VSB, and some very small bumps before the +12V rails settle down. In general, the performance here is pretty good. 

Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • LFCavalcanti
    Holy toaster!
    Reply
  • Onus
    Shades of the GX line; Coolermaster swings for the fences, but a competitor (pick one) in the outfield snags it and throws this one out trying to stretch a single to second base.
    Reply
  • MasterMace
    CM doesn't get to put a $450 price tag on something that isn't in the same park. That voltage regulation is disappointing.
    Reply
  • turkey3_scratch
    A lot of hype and little delivery for that price tag of course. Lower that price down to $200 and then we may be talking. The efficiency under low loads was quite poor. I'd like to bash the 5VSB regulation, though that's going to be unimportant and unrealistic with the majority of consumers, having load changes on that rail. Though if you are charging multiple devices I'd rather have it at 5V than 4.75V.

    At least the transient response performance was really good. The PWR_OK signal, eh. Aris, do you think that transient filter is really enough? I have a feeling it would fail EMI testing, only 4 y caps, 4 x caps, and 2 cm chokes on the unit.

    Overall, Cooler Master paired with the wrong OEM.
    Reply
  • Aris_Mp
    the transient filtering stage looks complete since it has more than the required X caps, however you can never know unless you actually test it. I have the equipment and knowledge but I lack the time to do it :)
    Reply
  • turkey3_scratch
    What are the exact requirements? I know what the ATX spec says but you have units like the FSP Hydro G 750 that failed by a good margin with 4 y caps, 2 x caps, and 2 cm chokes. So when talking about a 1200W unit with 4 y caps, 4 x caps, and 2 cm chokes, those 2 extra x caps are enough to do the trick?
    Reply
  • Aris_Mp
    it doesn't have to do with the Wattage but with the design.
    Reply
  • Nuckles_56
    The performance per dollar chart was great, it showed how badly overpriced this unit is and that there is a lot which could be improved on for the money spent on the unit
    Reply
  • Andi lim
    It's seem like the solid polymer caps on front side modular PCB's not from Nichicon, I think it belongs to Unicon taiwan ( UPT series ).
    Reply
  • jimmysmitty
    18352433 said:
    CM doesn't get to put a $450 price tag on something that isn't in the same park. That voltage regulation is disappointing.

    Sadly it is more than the AX1500i, lower efficiency and specs overall and a lower warranty (7 year vs 10 year).

    If someone is going to spend that much on a PSU It would be better to go for the Corsair.
    Reply