We would like to thank Rosewill for supplying the review sample.
Rosewill is not new to the Platinum-efficiency club since they already have a high efficiency series with their Fortress line-up; however, that series only includes PSUs of low to medium capacity without a modular cabling design in an attempt to keep it affordable and to attract the budget-oriented user without a vested interest in such features. Nevertheless, most users nowadays highly prefer modular PSUs to non-modular ones, which gave Rosewill additional incentive to include a high-end PSU in their offerings. So they co-operated with Super Flower to present the Tachyon series which does, in essence, consist of rebadged Super Flower Golden King PSUs. We have already reviewed many Platinum Super Flower PSUs in the past, so we are aware of their top performance, but this will be the first time that their high-end platform confronts our Chroma loaders.
The test subject of today's review will be a Tachyon with 1000 W capacity, which is the flagship model of not only the homonymous series, but of Rosewill's entire PSU portfolio. This unit features a powerful single +12V rail, goes fanless at lower loads, and is equipped with modular cables that, amongst others, include six PCIe and two EPS connectors, so it can handle up to three high-end VGAs and a server mainboard with two installed CPUs. The big Tachyon does, according to Rosewill, utilize a silent fan which, thanks to its auto fan speed control, operates with the lowest possible noise-output once engaged. Well, we will see about that given we already started taking noise measurements through the fan-speed data we gather in every other review. We should note that taking noise measurements during PSU testing is not that easy while the ultra-noisy Chromas is operating, and we had to devise a rather simple, but at the same time ingenious, method to be able to accurately evaluate the output noise of the PSU under testing conditions.
|Rosewill Tachyon 1000W Features & Specs
|Max. DC Output
||80 PLUS Platinum
||0°C - 50°C
||Over Voltage Protection
Under Voltage Protection
Over Current Protection
Over Power Protection
||140 mm Sleeve Bearing Fan (RL4Z S1402512HH)
||150 mm (W) x 86 mm (H) x 180 mm (D)
||ATX12V v2.31, EPS 2.92
|Price at time of review (exc. VAT)
The PSU carries the highest efficiency certification with 80 Plus Platinum, and the maximum operating temperature at which it is able to deliver its full power continuously is 50°C. Its protection features include everything except the crucial OTP (Over Temperature Protection), but such a wide operating temperature range does, thankfully, make OTP a little less useful to this Tachyon.
The fan has a 140 mm diameter and is, unfortunately, not equipped with ball-bearings, but with a plain sleeve bearing that doesn't last nearly as long. We expected a fan of higher quality to be used with such an expensive unit.
The unit's dimensions are larger because of the components needed to output 1 kW, but nearly any chassis available on the market should be able to accommodate this PSU since its length, although bigger than the normal 160 mm, isn't that much longer; that is, at least compared to monstrous PSUs like the Silverstone ZM1350.
Strangely enough, Rosewill states that this unit is ATX 2.31 compliant, although this doesn't stand since the latter spec requires at least two +12V rails and the Tachyon 1000 W only has one. However, this is nothing to whine about, and they probably filled this section of their PSU's specifications out in a hurry without priorly researching it properly. Finally, the warranty is five years long, which is a sufficient period for a high-end PSU, and its price tag is close to the Kingwin Lazer Platinium 1000W - one of its direct contenders.
|Rosewill Tachyon 1000W Power Specs
|Total Max. Power
The single +12V rail is powerful since it can almost deliver 1 kW. It will easily handle every system equipped with a three way SLI or Crossfire configuration. The minor rails, on the other hand, look weak with 100 W max combined power, but there is nothing to worry about since a contemporary PC won't draw more juice out of those two rails. This is why they are called minors, after all. Finally, the 5VSB rail can deliver up to 2.5 A, which looks like very little if we take into account the high capacity of this unit. A 1 kW unit should normally deliver >3A on this rail.
Cables & Connectors, Power Distribution
|ATX connector (560mm)
|4+4 pin EPS12V/ATX12V (625mm)
|8 pin EPS12V (570mm)
|6+2 pin PCIe (570mm+130mm)
|6+2 pin PCIe (500mm)
|SATA (500mm+130mm) / 4 pin Molex (+130mm+130mm)
||2 / 2
|4 pin Molex (500mm+130mm+130mm+130mm) / FDD(+130mm)
||4 / 1
Six PCIe and two EPS connectors are available at the same time, something common in most 1 kW PSUs. The number of available SATA connectors is sufficient for the category of the unit and the same applies to the number of the peripheral connectors.
The length of all cables should not cause compatibility issues with a large full-tower chassis, and the distance amongst connectors is good. Finally, the longer EPS cable uses thicker 16AWG gauges for lower voltage drops and the same applies to the wires that deliver +12V and earth to the main ATX connector. All the other connectors use the normal 18AWG wires.
Since this PSU features a single +12V rail, we do not have anything to comment on about its power distribution.
The Tachyon comes in a sturdy cardboard box with a carrying handle on top. The box's graphics design is nothing to write home about, and most of the front's real estate is occupied by a photo of the PSU with the fan-grill in the foreground. On the left side are badges for the unit's Platinum efficiency, the five-year warranty, and its modular cables, along with a description of the series and its capacity. The sides of the package only have an illustration of the series' name and Rosewill's logo.
A brief feature list with descriptions, a table of available connectors, and four more tables giving the power specifications on all Tachyon PSUs can be found on the rear side of the package. There is also an over-sized Platinum efficiency badge on this side; just to show off the high efficiency of the unit.
The PSU is meticulously protected by packing foam and is, on top of that, wrapped in a plastic bag. Next to it resides the pouch that holds all modular cables and the rest of the bundle.
The bundle includes the necessary modular cables, a set of fixing bolts, several zip ties for cable-management purposes, a user's manual, and an AC power cord.
The PSU features a black coating-finish that is fingerprint prone and not very scratch resistant. To be frank, we highly prefer double-layered texture coatings for high-end PSUs, given they are are fairly scratch resistant and look nicer. The classic honeycomb-mesh is used at the front, and the on/off rocker switch is installed under the AC receptacle, so it won't be easily accessible if you install the PSU with the fan facing up. The sides are not equipped with any decals and the same applies to the fan grill's center. This grants the PSU a nice and clean look some users will like; others may not appreciate the total absence of decals as much. At the rear, the modular sockets are covered by silicone caps, and all of them have the same number of pins, which allows you to connect any of the provided modular cables to any socket. Finally, the specifications label is installed on the bottom side, and the native cables are, as you can glean from the last of the above photos, fully sleeved back into the housing.
A Look Inside & Component Analysis
Before reading this page, we strongly suggest a look at this
article, which will help you understand the internal components of a PSU better.
As we already mentioned, all Tachyons are built by Super Flower. The platform they use is their high-end one – the same one that the Golden King models exploit. The design is modern, and the primary side has a half-bridge topology along with an LLC converter for a significant efficiency boost. The secondary side uses Synchronous design with two DC-DC converters for the generation of the minor rails. Also, the PSUs internals only use Japanese polymer and electrolytic caps provided by Nippon Chemi-Con, which is a clear indication of the PSU's high-end orientation.
Behind the AC receptacle is a small PCB holding some of the transient filtering components, namely two Y caps, one X cap, and a CM choke. The second stage of the transient filter on the main PCB includes another CM choke with two pairs of X and Y caps. Unfortunately, Super Flower refuses to introduce an MOV into any of their implementations, something we don't approve of.
The two parallel bridge rectifiers are bolted onto the APFC/primary heatsink. Their model number is US30KB80R
, and each one can handle up to 30 A, so they are too strong, even for a 1 kW capacity PSU.
In the APFC, two IPW50R140CP
mosfets separate the pulsating DC signal, and we also find two boost diodes, instead of the usual one, offering up their services. The hold-up caps are provided by Nippon Chemi-Con, but they don't share the same capacity. The larger one has 560 μF capacity and the smaller has 470 μF capacity. Both are rated at 105°C, 400 V and both belong to Nippon's KMQ series.
We removed the huge APFC choke to provide you a clear view to the NTC thermistor, which offers protection against large inrush currents, and the orange relay that cut's it off the circuit once the start-up phase finishes.
This small vertical daughter-board covered by EMI shielding-tape houses an NCP1653A
The two main switchers (Infineon IPW50R140CP) are configured in a half-bridge topology and do, along with an LLC resonant converter, provide high efficiency.
Τhe standby PWM controller is an ICE3B0565
On the secondary side, a great number (ten!) of IPP041N04N
fets rectify +12V. Each one can provide up to 80A in continuous mode, making ten far too much for the 996W that the +12V can, according to the specs, deliver. Also, enough polymer Nippon and some electrolytic caps (105°C; KZH; KZE and KY series) filter this rail.
Τhe minor rails are generated by two DC-DC converters housed on the same PCB. Four mosfets are used on each converter, and a metal shield protects them from interference.
The LLC resonant controller is a proprietary IC with model number SF29601. It sits on a vertical daughter-board located on the secondary side. It handles the primary choppers and all the protection features of the unit. Since this is a custom made IC, there is no info about these on the net. On the solder side of this small PCB is an LM324ADG
Quad Operational Amplifier. We should note that we used a photo taken from the internals of the Super Flower Golden King 1000 W, which uses exactly the same platform, since we couldn't get a clear photo of the SF29601 on the Tachyon.
Eight Nippon KY series caps on the front of the modular PCB provide extra ripple filtering to the DC outputs.
Soldering quality on the main PCB is really good, although it still doesn't reach Delta's and Seasonic's high-end implementations. Nevertheless, it does its job pretty well, as you will find out from the test results.
The fan carries Rosewill's logo but its model number (RL4Z S1402512HH) easily tells us that it is made by Globe Fan. It uses a sleeve bearing, which makes it quieter than a ball-bearings fan, but it doesn't last nearly as long. Its maximum speed is 1800 RPM when it delivers 135.74 CFM and outputs 36.7 dBA (according to the manufacturer). Finally, a small plastic baffle is attached onto the fan to direct the air towards the rear side of the unit.
The fan control circuit is installed on a small vertical daughter-board in the secondary side. A quality problem we spotted is that this small PCB is only held in place by several weak solder joints on its base. These solder joints completely detached from the PCB once we tried to disconnect the fan header, although we applied minimal force and were extra cautious. This means that strong vibrations (during shipping for instance) may cause these joints to detach as well, which would break the fan circuit, so the fan won't spin at any load/internal temperature. Such a fan's malfunction will, to make things worse, easily pass unnoticed since the fan only spins up at higher loads and increased temperatures, and the PSU isn't equipped with OTP to shut down operation once internal temperature go through the roof. An easy fix to this problem would be to apply some glue around the PCB to secure it in place. Some build-quality points where obviously lost here.
All measurements were performed using two Chroma 6314A mainframes equipped with the following electronic loads: six 63123A [350 W each], one 63102A [100 W x2], and one 63101A [200 W]. The aforementioned equipment is able to deliver 2500 W of load, and all loads are controlled by a custom-made software. We also used a Picoscope
3424 oscilloscope, a Picotech TC-08 thermocouple data logger
, a Fluke 175 multimeter, and a Yokogawa WT210 power meter. We also included a wooden box, which, along with some heating elements, was used as a hot box. Finally, we had at our disposal four more oscilloscopes (Rigol 1052E and VS5042, Stingray DS1M12, a second Picoscope 3424), and a CEM DT-8852 sound level meter. In this
article, you will find more details about our equipment and the review methodology we follow. Finally, we conduct all of our tests at 40 - 45°C ambient in order to simulate with higher accuracy the environment seen inside a typical system, with 40 - 45°C being derived from a standard ambient assumption of 23°C and 17 - 22°C being added for the typical temperature rise within a system.
Primary Rails Voltage Regulation
The following charts show the voltage values of the main rails, recorded over a range from 60W to the maximum specified load, and the deviation (in percent) for the same load range.
The following chart shows how the 5VSB rail deals with the load we throw at it.
The hold-up time is a very important characteristic of a PSU and represents the amount of time, usually measured in milliseconds, that a PSU can maintain output regulations as defined by the ATX spec without input power. In other words, it is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption. The ATX spec sets the minimum hold-up time to 16 ms at maximum continuous output load. In the following screenshot, the blue line is the mains signal and the yellow line is the "Power Good" signal. The latter is de-asserted to a low state when any of the +12V, 5V, or 3.3V output voltages fall below the undervoltage threshold, or after the mains power has been removed for a sufficiently long time to guarantee that the PSU cannot operate anymore.
Although the hold-up caps are of significant capacity, the effective hold-up time is much lower than the minimum allowed.
Inrush current or switch-on surge refers to the maximum, instantaneous input-current drawn by an electrical device when first turned on. Because of the charging current of the APFC capacitor(s), PSUs produce large inrush-current right as they are turned on. Large inrush current can cause the tripping of circuit breakers and fuses and may also damage switches or relays; as a result, the lower the inrush current of a PSU right as they are turned on, the better.
Thanks to its large APFC caps, the inrush current that the Tachyon 1000 W registers is high and close to the reading of the monstrous Silverstone ZM1350 and Enermax EMR1500GT units.
Voltage Regulation and Efficiency Measurements
The first set of tests revealed the stability of the voltage rails and the efficiency of the Tachyon-1000. The applied load was equal to (approximately) 20%, 40%, 50%, 60%, 80%, 100% and 110% of the maximum load that the PSU can handle. In addition, we conducted two more tests. In the first test, we stressed the two minor rails (5V and 3.3V) with a high load while the load at +12V was only 2 A, and, in the second test, we dialed the maximum load that the +12V rail could handle while the load on the minor rails was minimal.
| Voltage Regulation & Efficiency Testing Data
Rosewill Tachyon 1000W
Efficiency is very high throughout all load levels and the PSU did, on top of that, prove that it can easily deliver 110% of its maximum rated capacity at 46°C ambient. Also, voltage regulation on all rails was good, especially at +12V, given it registered a deviation very close to 1%. We noticed something pretty strange in the fan's operation during the 80% load test. Instead of a linear and smooth RPM increase, the fan throttled up into full speed instantly. This was unexpected and the fan should increase its speed linearly and not in such a peculiar way since it resulted in a sudden rise of noise output.
Using the efficiency results from the previous page, we plotted a chart showing the efficiency of the Tachyon-1000 at low loads and at loads equal to 20-110% of the PSU's maximum rated load.
For a discussion of these results, see the text at the end of the previous page.
Efficiency at Low Loads
In the next tests, we measured the efficiency of the Tachyon-1000 at loads much lower than 20% of its maximum rated load (the lowest load that the 80 Plus Standard measures). The loads that we dialed were 40, 60, 80, and 100 W (for PSUs with over 500 W of capacity). This is important for settings where the PC is in idle mode with power saving turned on.
| Efficiency at Low Loads
Rosewill Tachyon 1000W
Efficiency at low loads is simply amazing, given the high capacity of this unit. Super Flower did an excellent job with this platform and managed to combine high capacity with high efficiency throughout the entire load range; not easy to achieve.
The ATX spec states that the 5VSB standby supply's efficiency should be as high as possible and recommends 50% or higher efficiency with 100 mA of load, 60% or higher with 250 mA of load, and 70% or higher with 1 A or more of load.
We will take four measurements: one each at 100, 250, and 1000 mA , and one with the full load that the 5VSB rail can handle.
| 5VSB Efficiency
Rosewill Tachyon 1000W
Unfortunately, efficiency at 5VSB doesn't keep up with the efficiency registered by the other rails. Only with tests #3 and #4 does it manage to surpass the minimum allowed thresholds set by the ATX spec, and its efficiency is nothing special, even at full load; we have seen PSUs register well over 80% efficiency on this rail. Clearly the 5VSB rail is not this unit's strong point since it is neither efficient nor strong enough for a 1 kW PSU.
Power Consumption in Idle & Standby
In the table below, you will find the power consumption and the voltage values of all rails (except -12V) when the PSU is in idle mode (powered on but without any load on its rails) and the power consumption when the PSU is in standby mode (without any load at 5VSB).
| Idle / Standby
Rosewill Tachyon 1000W
Vampire power is lower than 0.5 W, making the PSU compliant with the ErP Lot 6 2013 directive that will come into effect very soon.
Fan RPM, Delta Temperature and Output Noise
The cooling fan's speed (RPMs) and the delta difference between input and output temperature are illustrated in the following chart. The following results were obtained at 40°C - 45°C ambient.
The following chart shows the cooling fan's speed (RPMs) and its output noise. We measure the fan's noise from 1 meter away. The background noise in our lab was close to 30 dBA during testing.
Cross Load Tests
For the generation of the following charts, we set our loaders to auto mode through our custom-made software before trying over a thousand possible load combinations with the +12V, 5V, and 3.3V rails. The voltage regulation deviations in each of the charts below were calculated by taking the nominal values of the rails (12V, 5V, and 3.3V) as point zero. We should note here that we only run this test with PSUs that have a capacity equal to or lower than 1000 W, since it takes a long time to run, and the completion time increases exponentially as the capacity of a unit increases.
+12V Voltage Regulation Chart
5V Voltage Regulation Chart
3.3V Voltage Regulation Chart
+12V Ripple Chart
5V Ripple Chart
3.3V Ripple Chart
5VSB Ripple Chart
Advanced Transient Response Tests
In these tests, we monitor the response of the PSU in two different scenarios. First, a transient load (10 A at +12V, 5 A at 5V, 5 A at 3.3V, and 0.5 A at 5VSB) is applied to the PSU for 200 ms while the latter is working at a 20% load state. In the second scenario, the PSU, while working at 50% load, is hit by the same transient load. In both tests, we measure the voltage drops that the transient load causes using our oscilloscope. The voltages should remain within the regulation limits defined by the ATX specification. We must stress here that the above tests are crucial since they simulate transient loads that a PSU is very likely to handle (e.g., booting a RAID array, an instant 100% load of CPU/VGAs, etc.) We call these tests "Advanced Transient Response Tests", and they are designed to be very tough to master, especially for PSUs with capacities lower than 500 W.
| Advanced Transient Response 20%
| Advanced Transient Response 50%
The PSU's response to dynamic loads is excellent. The strongest performer was the +12V rail; it managed to register the lowest deviation amongst all rails. Also, the 3.3V rail, which showed the largest deviation, managed to stay well above our low 3.2V limit for these tests. The unit's overall performance on these tests is great!
Below, you will find the oscilloscope screenshots that we took during Advanced Transient Response Testing.
Transient Response at 20% Load
Transient Response at 50% Load
Turn-On Transient Tests
We measure the response of the PSU in simpler scenarios of transient loads - during the power-on phase of the PSU - in the next set of teset. In the first test we turn the PSU off, dial the maximum current that the 5VSB can output, and then switch on the PSU. In the second test we dial the maximum load that +12V can handle and we start the PSU, all while the PSU is in standby mode. In the last test, while the PSU is completely switched off (we cut off power or switch off the PSU's on/off switch), we dial the maximum load that the +12V rail can handle before switching the PSU on from the loader and restoring power. The ATX specification states that recorded spikes on all rails should not exceed 10% of their nominal values (e.g., +10% for 12V is 13.2V and for 5V is 5.5V).
No visible spikes/overshoots on all three tests, and the only thing that makes this PSU miss perfection by a very small margin is the minor step that the +12V rail registered during the last test.
You will see the ripple levels that we measured on the main rails of the Tachyon-1000 in the following table. The limits are, according to the ATX specification, 120 mV (+12V) and 50 mV (5V, 3.3V, and 5VSB).
| Ripple Measurements
Rosewill Tachyon 1000W
Ripple suppression is excellent, something we expect from a Super Flower product and, in particular, this platform. The +12V rail stayed well below 35 mV, even during the 110% load test, and the minor rails behaved really well. Yes, the 3.3V rail registered higher ripple than the 5V one, but it still managed to stay around the mean of the ATX limit.
Ripple at Full Load
In the following oscilloscope screenshots, you can see the AC ripple and noise that the main rails registered (+12V, 5V, 3.3V, and 5VSB). The bigger the fluctuations on the oscilloscope's screen, the bigger the ripple/noise. For all measurements, we set 0.01 V/Div (each vertical division/box equals to 0.01 V) as standard.
Ripple at 110% Load
Ripple at Crossload 1
Ripple at Crossload 2
The following graph shows the total performance rating of the PSU in comparison to other units we have tested before. To be more specific, the tested unit is shown as 100% and all other units' performance is relative to it. If you want to know the exact method that we use to calculate the performance rating of each PSU, read this
Performance per Dollar
For most of you, the following graph is the most interesting since it shows the performance per dollar of the PSU that you may consider buying. We looked up the current USD price of each PSU on the popular online shop Newegg and used it, along with the relative performance numbers to calculate the performance-per-dollar index. If Newegg didn't have a stock of a specific unit, we searched for it at other popular online shops (e.g., TigerDirect, Amazon) and, finally, if the unit was not sold in the USA, we searched the product at popular EU shops (e.g., Caseking) and then, if found, converted its price to USD (w/o VAT). Note that, in the following graph, all numbers are normalized by the rated power of each PSU.
Value and Conclusion
- The Rosewill Tachyon 1000 W retails for $219.99
- Delivered full power at 45°C
- Good price/performance ratio
- Highly efficient
- Excellent ripple suppression
- Tight voltage regulation
- Good response in dynamic loads
- Semi-fanless mode
- Uses nothing but Japan-made capacitors
- Five-year warranty
- Small hold-up time
- Weird fan profile
- No MOV in the transient filter
- Weak 5VSB rail (for the unit's category)
- Fan quality
||The fresh Tachyon 1000 W includes all the necessary features for a successful presence on the market. For starters, it is based on Super Flower's top platform, something that grants it extra-high efficiency, tight voltage-regulation, excellent ripple-suppression, and a very good response to dynamic loads, which will be its daily routine in real-life scenarios. It, on top of that, uses nothing but Japan-made caps, which tend to last much longer than Chinese caps. They also age much slower, and that allows them to maintain the same level of performance for much longer. The PSU also operates in fanless mode at low loads – outputting almost no noise. Finally, the five-year warranty that Rosewill provides will ensure that the future buyer doesn't have to worry about the PSU for a fairly long time.|
Its downsides, as far as I was able to spot them, are its small hold-up time, which is much lower than the minimum allowed by ATX spec, the absence of an MOV from the transient filtering stage, which means that you should use this PSU along with a surge protector in order to be fully protected, and the fan profile that will need some tuning. Actually, the fan circuit acts as an on/off circuit in my sample since the fan suddenly kicked into full speed from low RPM once I increased the temperatures inside my hotbox. Its speed increase should be linear and not so sharp.
To sum up, the Tachyon 1000 W is a high-performance PSU that manages to register a fairly good price/performance ratio thanks to its decent pricing scheme. This unit should be on the top of your list if you need such power and want the highest efficiency money can buy in this category along with top performance.