Today's Hard|Forum Post
Today's Hard|Forum Post

Enermax Revolution SFX 650W Power Supply Review

The small form factor segment has been hot for a while now when it comes to enthusiast PC builders and Enermax is entering the SFX fray today with the Revolution SFX 650W PSU. It touts fanless modes under 30% load, 100% Japanese capacitors, and complete flat flexible cables for easier routing in tight cases.



Today, we see that an old dog that has learned a new trick as long time power supply producer Enermax has brought us the very first SFX unit we have seen from the company in the guise of the Revolution SFX 650W. While this is obviously not the first SFX unit we have seen, it is the first we have seen from Enermax and it is the largest capacity SFX unit we have seen (not SFX-L like the SilverStone SX700-LPT). So, in Enermax' first SFX outing it is certainly going big in this small realm. The question is, does the Revolution SFX 650W provide us with a pint sized revolution that packs a punch or just a pint sized revolution? Let’s see.

HardOCP’s testing methodology is intended to very much push power supplies to their advertised wattage rating in temperatures that will represent some of the hottest computer enthusiast cases. So if a unit passes all our testing it is definitely not something to take lightly. In fact we expect more power supplies to fail our testing than make it through unscathed.

Build Quality

The build quality of the Enermax Revolution SFX 650W starts things off today on what turns out to be a generally good note overall. Externally, the Revolution SFX 650W is certainly well done for its design and in keeping with Enermax' general aesthetic. The fit and finish is very much like we have seen from some of the nicer Enermax offerings and we see FlexForce style cabling included which will help reduce some bulk in tight spaces. When we move to the interior of the unit, things look a bit more mixed than on the exterior but things are still generally well done for an SFX form factor product. The topology is modern and the unit sports standard capacitors from Nichicon and Nippon Chemi-con. The fan used today is just an 80mm model from Yate Loon but it is a ball bearing design which is good. The downsides we see in the interior are a few areas where the soldering was not great and the solid capacitors are Su'scon's. That all said, this is backed up documentation that is, again, not what we are used to seeing from Enermax in the past but it does have a 5 year warranty.

Load Testing

Today, the load testing results for the Enermax Revolution SFX 650W paint a picture of David versus the Goliath in a sense. Here, we see that the voltage regulation saw the 12v rail drop by up to 0.08v while the minor rails dropped by 0.08 on the 5v rail and 0.09v on the 3.3v rail. This means that this unit was better than the Cyonic AU-650x, almost better than the VIVO 24K 650W, almost better than the Thermaltake Toughpower DPS G 650W, and barely trailing the FSP Hydro G 650W. Now, as all of those units are physically twice the size of the unit, we see why we have sort of a David versus the Goliath thing going today since this unit is competitive with these units and it seems like it should not be. Interestingly though, when we look at some of the other recent "David's" we see that the Revolution SFX 650W was mixed with both the Thermaltake Toughpower SFX 600W and the Corsair SF600. When we look at this unit’s efficiency, we see that it was 87.56% to 90.81% efficient at 120v and 85.60% to 90.05%efficient at 100v during our tests today. Then, when we ran the 80 Plus tests, we saw efficiency values of 88.57%-91.29%-87.28% for the Revolution SFX 650W. This puts this unit right in its claimed 80 Plus Gold category. Beyond that, the Revolution SFX 650W also passed the Torture Test in fine shape which is yet another good result.

The Transient Load Tests results for the Enermax Revolution SFX 650W are, more or less, the opposite of what we saw from our regular load tests as this unit goes from being better than we would expect to a bit worse than we hoped. When directly loaded, the 12v rail showed a peak change of ~400mV and the 5v rail had a peak change of ~200mV. The unloaded 5v peak change during the 12v load was ~160mV. Now, in the first line it says that these results are the opposite of what we saw in our regular load tests. The reason for that is the fact that, here, this unit trails every unit we have compared the Revolution SFX 650W to today including the VIVO 24K 650W, FSP Hydro G 650W, Thermaltake Toughpower DPS G 650W, Cyonic AU-650x, Thermaltake Toughpower SFX 600W, and Corsair SF600. That is certainly not as good as we saw in the regular load tests and something that this unit could improve upon going forward.

DC Output Quality

Moving on to the DC Output Quality today, we see that the Revolution SFX 650W is moving back into that competitive realm that is much more like what we saw in our regular load tests. During our testing today, the peak 12v trace amplitude was ~25mV while the peak 5v and 3.3v trace amplitudes were also ~25mV. Now, while each of these results are well within the ATX12v specification limits, the 5v and 3.3v rails are hitting ~1/2 of the ATX12v specification limit which initially made me a bit concerned about how this unit would fare relative to other units we have seen, As it turns out though, the Revolution SFX 650W turns in a very middle of the pack performance in a lot of ways as it was mixed with the Thermaltake Toughpower SFX 600W and Cyonic AU-650x, trailed the Corsair SF600, VIVO 24K 650W, and FSP Hydro G 650W but almost bests the Thermaltake Toughpower DPS G 650W. So, while not stunningly good, this unit seems to be right back in the competitive ballpark.


The Enermax Revolution SFX 650W is an interesting product for a lot of reasons. Often, however, the word interesting should actually be written as "interesting" and when you look at a 650W 80mm fan cooled SFX unit it does make one think that the quotation marks should be there around interesting. That said, the Revolution SFX 650W is very efficient and it features a semi-fanless operation. Due to this, the unit was actually very well behaved at low loads. Once the fan did turn on, it was generally acceptable in its noise profile once the fan settled in. Obviously, the unit was not absolutely silent but if you were to use this in an average SFF build it is unlikely that you would notice this unit's noise output. All in all, it seems like Enermax has done a good job in this aspect of the units performance.

Paul's Thoughts:

The SFX power supply market seems to be growing at an ever increasing clip over the last few years and, with Enermax jumping in the mix today, it seems like just about all of the major brands will have some sort of quality offering in this segment soon. As such, this segment is probably going to go from "under-saturated" to "competitive" very quickly. When that happens it is always nice to have something in hand about your product to differentiate it from everyone else. With the Revolution SFX 650W, today, it seems that the biggest differentiator is capacity. To date, we have seen SFX units top out at 600W and the Revolution SFX one ups those units by going to 650W. Other than that though, the Revolution SFX 650W performs, and is appointed, like the slightly smaller 600W units we have seen before it when we look at all of our metrics together. Sure, there are a few tests where this unit is better, even with it's larger capacity, but there are also some where it is not as good. So our differentiator today is capacity. Hopefully that won't be what Enermax rests on for too long as other brands (like SilverStone) have products in the SFX-L category that are pushing up to 800W in a form factor that is only slightly larger. With that being the case then, it is only a matter of time before someone drops a 700W, or maybe even 800W SFX unit on the market. At which time the 650W Revolution will need another trick up its sleeve. Until then though, the Revolution SFX 650W's large capacity and competitive tests results make this unit one that posses serious issues for its competitors and, from a users stand point, that is a good thing!

The Bottom Line

With the Enermax Revolution SFX 650W being the first SFX power supply we have seen from Enermax, we had more questions than answers coming into today's review. Over the course of working with this unit it, however, answered most all of those questions with the correct answers. Occasionally, we got some not-so-good answers but they were the minority of cases such that, in the end, this unit was commendable overall. What lead us to that conclusion was the (mostly) very good build quality, the excellent efficiency, the very good voltage regulation, and the fact that the unit was very quiet. A few areas where the Revolution SFX 650W could use some improvement (like the Transient Load Tests) did exist but, overall, the unit did indeed do well. That, then, brings us to the last item of the day; the price. Today, the Revolution SFX 650W can be found for $117.92 with Free Prime Shipping. At that price, it is just a touch cheaper than both 600W SFX units we compared it to today while being just about smack between those in performance. Essentially, this is not a killer price nor is it a horrible price. In fact, it might be the "right" price relative to its performance in the market. Sure, we'd like to see it bit less expensive because we as a society would love to see everything be dirt cheap and ridiculously high quality (as unrealistic as that is) but $117.92 is a fair price in this market. So, if you are in the market for a large capacity SFX power supply the Revolution SFX 650W is a solid option. Also worth mention is that the Enermax Revolution SFX 650W comes supplied with an SFX-to-ATX PSU adapter bracket that allows for installation in ATX or Micro-ATX cases.

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Enermax Revolution SFX 650W PSU