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Final Analysis
The Onyx 650 gives us a nice surprise. We expected to see Riotoro utilizing an older platform. Instead, we found a much more modern design armed with circuits typically found in higher-efficiency PSUs.
On top of that, its selection of filtering capacitors is great for this price range. Besides electrolytic caps, a significant number of polymer ones are also used. It's only strange that Riotoro's higher-end Enigma 850 uses a 85°C bulk cap, while the affordable Onyx 650 includes higher-temperature (105°C) caps in the APFC converter. Unfortunately, due to the low combined capacity of its bulk caps, the Onyx 650 registers an unacceptably low hold-up time.
The PR-BP0650-SM's overall performance is good enough, but in our ripple suppression tests it loses to the CX650M big-time. That's Riotoro's main competitor, so it really needed to fare better.
Riotoro is a new company, and its decision to enter the PSU market with two product families addressing mainstream and mid-range customers seems like the right move. The Onyx 650 is semi-modular. Only its necessary cables are native, and there are two eight-pin sockets on its modular panel, so you have the option to add a second EPS connector or another pair of PCIe ones if you can find the corresponding cable for sale. In any case, it is good to have an upgrade path since this PSU has enough capacity to support those extra connectors.
The Onyx 650 is based on a modern platform that's built well. Its performance is decent; however, a few items need more attention. For starters, the PSU should be equipped with larger bulk caps in order to improve its hold-up time. A more relaxed fan profile and a higher-quality fan would dramatically improve this unit's noise levels, too.
Of course, we understand that those changes would affect the PR-BP0650-SM's price tag, Bulk caps are expensive in general and a good fans aren't cheap. The only change that could be implemented for free would be an updated fan profile. Dialing it back just a little bit shouldn't affect the PSU's long-term reliability by much.
In our opinion, Riotoro is on the right track, and Great Wall is a good OEM. So we expect more from this company in the future. Two lower-capacity Onyx family members would help Riotoro cover a larger market segment and probably boost the Onyx line's sales. More efficient GPUs that don't need monster power supplies are popular right now. However you should pay attention to your system's energy needs. Under full load, the PC shouldn't apply a load close to the PSU's maximum power, but rather you want to see it around 70-80%. That way you won't over-stress the PSU, while still enjoying maximum efficiency.
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