Seasonic's 750W Focus Plus Platinum PSU turns heads at its current price, no doubt about it. We don't know how the company managed to hit such an attractive value point while maintaining strong performance, excellent build quality, and a 10-year warranty. Its SSR-750PX is the best 750W PSU you can buy in the $100 to $130 range, and it doesn't surprise us that Seasonic is trying hard to satisfy the heavy demand for its newest platforms, especially the Focus.
In the past, Seasonic's engineers played it safe with aggressive fan profiles for increased airflow. As a result, many of its previous-generation PSUs were fairly noisy. But with the fresh Prime and Focus models, they thankfully took a different approach. The high-efficiency Focus models feature semi-passive modes and loose fan profiles, even under tough operating conditions. It is nice to see key OEMs like Seasonic realizing that performance and reliability should go along with mild acoustics.
The SSR-750PX offers great load regulation, high efficiency, and amazing ripple suppression. On top of that, it is compact and comes with a large number of modular cables, including two EPS and four PCIe connectors. We also like that Seasonic's semi-passive mode can be deactivated, allowing the PSU to be installed with its fan facing downwards. In our opinion, all manufacturers should provide the ability to deactivate their semi-passive fans. Because this costs a bit more, many of them choose not to give you that option.
Seasonic's build quality is high. In addition to fairly good electrolytic and polymer capacitors, the company also uses an FDB fan, which should last a long time. A 10-year warranty is another clue that this platform was designed to operate reliably.
As you can tell, we're impressed with the new Focus platform. However, since all of our tests allow us to be extra picky, we did spot a couple of areas where there is room for improvement. First, the 3.3V rail's transient response isn't particularly good. Normally it should remain within 3% in all scenarios. This rail might be used lightly by most modern PCs, but it's still required by the ATX spec and needs to perform well. We're also bothered by the SSR-750PX's EMI filter, which apparently needs a little tuning in order to be more effective. Controlling conducted (and radiated) EMI emissions is tough, but we are sure that Seasonic's engineers are up to the task. And as it pertains to protection features, we believe that over-power protection should be set around 120% of the PSU's maximum-rated capacity instead of 135%. The over-current protection triggering point at 5VSB should be much lower as well.
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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, Purch Media, are financially involved with Cybenetics. Aris does not perform the actual certifications for Cybenetics.