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Rosewill Tokamak 1500 PSU Review

Rosewill enters the 80 PLUS Titanium efficiency club with two Tokamak models boasting 1.2kW and 1.5kW of capacity. The highest-end version is on our bench today, and we're eager to check out its Enhance-based platform.

Transient Response Tests

Advanced Transient Response Tests

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

Ιn these tests, we monitor the Tokamak 1500'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, Rosewill's contender 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

VoltageBeforeAfterChangePass/Fail
12V12.113V12.050V0.52%Pass
5V5.046V4.947V1.96%Pass
3.3V3.365V3.244V3.60%Pass
5VSB5.020V4.962V1.16%Pass

Advanced Transient Response at 50 Percent

VoltageBeforeAfterChangePass/Fail
12V12.067V12.001V0.55%Pass
5V5.038V4.943V1.89%Pass
3.3V3.356V3.241V3.43%Pass
5VSB5.002V4.941V1.22%Pass

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The +12V rail's transient response is excellent! Of course, we didn't expect anything less from such a high-capacity PSU. Performance is pretty good on the other rails too, though we'd like to see deviations within 3% during both tests.

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

Transient Response At 20 Percent Load

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Transient Response At 50 Percent Load

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Turn-On Transient Tests

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

For the first measurement, we turned off the Tokamak 1500, dialed in the maximum current its 5VSB rail could output, and switched the PSU back on. In the second test, we dialed the maximum load the +12V rail could handle and started the 1500W supply while it was in standby mode. In the last test, while the PSU was completely switched off, we dialed the maximum load the +12V rail could handle before switching it back 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).

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The 5VSB rail registers a fairly smooth spike, and during the second test we notice a small wave. It's only in the third test that we see a notable spike, though it's way below the limit defined by the ATX specification.

  • Onus
    With GPU-based mining days long gone, I don't ever see myself in the market for a beast like this; but no power switch? That's...bizarre.
    Reply
  • Brian_R170
    I keep reading that muti-GPU systems are on the decline, so what's continuing to drive development of PSUs with >1KW output?
    Reply
  • leclod
    Same here...
    Reply
  • kittle
    18972155 said:
    I keep reading that muti-GPU systems are on the decline, so what's continuing to drive development of PSUs with >1KW output?
    Im curious too -- i can only speculate the marketing folks are still pushing the "bigger number == better" mantra
    Reply
  • JohnnyLucky
    There are still some hardcore enthusiasts and a few who want bragging rights. I couldn't help but notice quite a few cons.
    Reply
  • captaincharisma
    there is always someone out there whether they are an enthusiast or a first time system builder that will blindly buy this because after all "bigger is better" lol
    Reply
  • turkey3_scratch
    Rosewill always goes with a very simple exterior. I like it. This is also a very unique name. I'm sick of boring PSU names. Tomakamek. Sounds like some sort of ancient island, I like it.
    Reply
  • SkyBill40
    The reactor of the same name was the first thing that came to mind upon seeing it and even before it was mentioned in the write up. An interesting choice, no doubt. Given the output, I guess it's somewhat fitting.
    Reply
  • daglesj
    Must admit rarely use the power switch at the back. Quicker to know that a pulled power lead means 'off'...completely. No great loss.
    Reply
  • lunyone
    So ready for this to be in a m-ITX build! Lol! Too bad it isn't modular! <sarcasm over>
    Reply