Riotoro Onyx 650W PSU Review

Riotoro is a new company trying to enter the tough PSU market where big brands dominate. We already reviewed Riotoro's Enigma 850 and determined that it's essentially a clone of Corsair's CS850M, since both units are based on the same Great Wall platform. However, this company has a second family in its portfolio; the mainstream Onyx line-up consists of two members with 650W and 750W capacities. The lower-level Onyx power supplies also employ a Great Wall platform. It isn't as efficient, but it does cost less.

Today we're reviewing the 650W Onyx model, pitting it against popular competitors in this category like Corsair's CX650M. Since we don't have many direct comparisons in our database, we're also including several mid-range and high-end products in order to illustrate the differences between mainstream PSUs and pricier alternatives.

Again, the Onyx 650 is based on a GW platform that's 80 PLUS Bronze-certified. Cybenetics also certified this PSU, and it carries the ETA-C and LAMBDA-C badges.

It sports a semi-modular design with just two native cables. And because of its low efficiency, Riotoro doesn't expose a semi-passive mode. This is a good thing, as increased thermal loads could be catastrophic for reliability over time. While a $70 price tag is certainly nice, the PR-BP0650-SM has to do battle with compelling options from Corsair and EVGA.

Once we gets into this PSU's guts, we'll know more about its expected longevity. When we reviewed the Enigma 850, we didn't like that its bulk cap was only rated at 85°C. Thankfully, Riotoro's Onyx 650 is blessed with high-quality bulk caps. Of course, it looks weird that the higher-end model uses lower-quality bulk caps than the entry-level product. Apparently, someone over at Riotoro wasn't paying close enough attention to the specs.


The maximum operating temperature at which Riotoro's PR-BP0650-SM can deliver its full power continuously is limited to 40°C, even though the ATX spec recommends 50°C. In any case, we don't believe that there are many power supplies out there able to truly satisfy this recommendation for extended periods of time. They might be alright serving up full power for 10 or 20 minutes at 50°C, but for 24/7 operation under full load at the same temperature, a PSU has to be specially designed with components resilient to heat and a highly capable fan.

Power Specifications

Max. PowerAmps25255430.8
Total Max. Power (W)650

The minor rails are quite strong, reminding us of previous-generation PSUs. Riotoro also arms its PR-BP0650-SM with a capable +12V rail able to output up to 54A. Finally, the 5VSB rail has enough capacity for a modern system.

Cables & Connectors

Native Cables
DescriptionCable CountConnector Count (Total)Gauge
ATX connector 20+4 pin (550mm)1118-20AWG
4+4 pin EPS12V (620mm)1118AWG
Modular Cables
6+2 pin PCIe (550mm+120mm) 1218AWG
SATA (450mm+110mm+110mm)2618AWG
Four-pin Molex (450mm+120mm+120mm)1318AWG
FDD Adapter (+100mm)1120AWG

Only the necessary cables are native: the ones hosting the 24-pin ATX and EPS connectors. Given the mainstream category that this PSU belongs to, we didn't expect more than a couple of PCIe connectors or two EPS cables. However, if you want to add more connectors, there is an available eight-pin socket on the unit's modular panel that can accommodate an extra EPS or PCIe cable. What we don't know is whether Riotoro plans to sell extra EPS and PCIe cables separately.

Power Distribution

Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.

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