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The strongest member of the Phanteks AMP line achieves high performance but not silent operation. Given the efficient platform, the fan speed profile could be more relaxed. This unit doesn't have the oversized heat sinks that the similar-capacity Asus ROG Strix model utilizes, which is based on the same platform, but still, the thermal images that we took prove that there is no need for such high airflow. Moreover, although the ripple suppression is good, yet with lower ripple levels at +12V (<20mV), this power supply would be notably close to its primary opponent, the Corsair RM750x.
The recent additions in the ATX spec, which apply from 2020, require among others for higher than 70% efficiency at 2%, of the PSU's max-rated-capacity, load, and for a power-ok delay signal within 100-150ms. The AMP 750W doesn't meet those requirements, so at some point, Phanteks should consider upgrading the platform to be fully compatible with the newest ATX spec. The only problem is that this will affect the production cost, hence the final price of the product will be affected.
For users that don't mind the increased noise output under higher loads, but want a reliable and efficient power supply, with compact dimensions, the Phanteks AMP 750W is the right choice if you find it at a similar or lower price than the same-capacity Seasonic Focus Plus model. On the other hand, if you need to build a dead-silent system and require a suitable power supply, the Corsair RM750x, and RM750, along with the Asus ROG Strix 750W, are better options.
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Disclaimer: Aris Mpitziopoulos is Tom's Hardware's PSU reviewer. He is also the Chief Testing Engineer of Cybenetics and developed the Cybenetics certification methodologies apart from his role on Tom's Hardware. Neither Tom's Hardware nor its parent company, Future PLC, are financially involved with Cybenetics. Aris does not perform the actual certifications for Cybenetics.
Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.