The question of “which power supply is the best?” comes up quite
often. The PC power supply can sometimes be the culprit behind system instability;
the pc won’t boot, has to be restarted two or three times to completely boot,
crashes, freezes or spontaneously reboots. Which PC power supply is the best?
Zalman, FSP, Enermax and SilenX are four more that are put to the test so you
can find out.
Who knew that buying a power supply could be complicated. Isn’t it just a metal
octopus stuck inside a PC case? Power supply specifications can be quite deceiving
as our article Power
Supplies: The Shocking Truth explains. Power supplies are designed with
a wide variety of PC case layouts in mind and not every power supply will work
in every PC case. It would be frustrating to purchase a new power supply only
to find out the leads are not long enough or there are enough power connectors
for the system configuration. It would be even more frustrating to continue
to be stuck with a system that still isn’t stable.
Four sent us their favorites to be scrutinized; Enermax,
FSP Group, SilenX
and Zalman.
Zzzzzzzap!
First and foremost a power supply is an electrical device which, if not used
correctly, has the ability to damage components, cause bodily harm or even death.
Do not remove the cover or modify a power supply if not qualified or certified
to do so…EVER.
Enermax has long been on the favorites list. It is one of the power supplies
with the longest cables which is of extreme benefit to those with extremely
large cases and a detriment to others with smaller 17″ towers. Enermax
power supplies are dual fan.
The back grill area is almost entirely slotted for air movement through the
power supply.
Enermax has the standard Molex connectors and a dedicated connector to monitor
one of the cooling fans. There would be no need to mention the standard Molex
connectors except on what will be learned by looking at other power supplies.
Enermax has elected to include a 4-pin Molex to dual SATA power connectors
instead of changing out Molex connectors right on the wire. There are pros and
cons to this. The pro is that Enermax can stick SATA POWER on their boxes as
if it were a new and improved feature. It’s also a convenient benefit for those
that are migrating to SATA drives. The third pro is that none of the existing
4-pin Molex connectors are sacrificed on the wire for those that don’t have
SATA drives. The con is that it’s extra wire that has to be managed.
The Enermax power supply interior is of quality manufacture. All wires are
tight and secure. Enermax is the only power supply in the test group to sleeve
both the ATX cable and then the P4, 12 volt and extra power cable.
The heatsink is relatively small compared to others. The cooling fans run at
a higher RPM and CFM to compensate.
Two Globe Fans provide cooling power for the PSU. The intake fan is 92mm. and
produces 52.5 CFM at 32.8 dBA maximum noise.
The main 80mm. exhaust fan turns at 3000 RPM producing 39.8 CFM at 32.6 dBA.
A convenient feature of Enermax power supplies are the fan connectors. Changing
out a fan, if ever one should fail and none have for two years in my own Enermax
PSUs, is easy. The connector can be pulled, cut and rewired to a new fan then
plugged back in.
| Volt line | +3.3 | +5 | +12 | -12 | -5 | +5 Vsb |
| Amps | 35 | 35 | 33 | 1 | 1 | 2.2 |
| Watts | 115.5 | 175 | 396 | 12 | 5 | 11 |
| combined |
220
|
|||||
| combined |
na
|
|||||
Fortron Source is a company with much more than meets the eye. FSP provide
OEM products for other brand names including Zalman and SilenX included in this
comparison. The FSP 400-60PNU power supply is the most cost effective of the
comparison group and the one with the most “flashy” appeal.
The 120 mm. cooling fan speed is manually adjusted by a rheostat at the rear
of the unit.
The Molex connectors feature a grip which is a convenient touch except with
ATI video cards that require additional power. The grip impedes the insertion
of the Molex connector to the video card.
FSP dedicates one lead for a single SATA power connector. This is an affordable
enthusiasts power supply and most enthusiasts may run RAID 0 drives therefore
two SATA power connectors on a lead may have been a more appealing touch.
Power supply “guts” are more or less standardized. What does noticeably
change are the heatsinks. FSP heatsinks are considerably larger than Enermax.
Note that the fins are horizontally aligned and not vertically. This design
pattern will increase the amount of surface area to radiate heat compared to
the vertical fin design of the Enermax unit.
FSP calibrates the PSU before it leaves the factory but if shipping should
affect the voltage calibration then the PSU can be tweaked via the adjustment
screw circled in the following image.
Occupying the entire bottom of the PSU is a 120mm. fan turning at a maximum
of 2600 RPM pushing a whopping 78 CFM at 43 dBA. The pitch of a 120mm. fan is
lower than a smaller version at the same dBA thus it can be perceived as quieter.
At low speed setting the fan is almost inaudible.
The fan box is acrylic which is wrapped in a LED strip to give it its glow.
An enthusiast could wire this LED strip to an outside switch to gain manual
on/off to this lighting effect.
| Volt line | +3.3 | +5 | +12 | -12 | -5 | +5 Vsb |
| Amps | 28 | 30 | 18 | 0.8 | 0.3 | 2.0 |
| Watts | 92.4 | 150 | 216 | 9.6 | 1.5 | 10 |
| combined |
220
|
|||||
| combined |
380
|
|||||
SilenX aren’t a manufacturer of power supplies. SilenX can be thought of as
a specialty supplier who take a manufacturer’s OEM product, in this case FSP,
and adjust its design to fit a niche market.
Without a doubt SilenX is silent. At less than 14 db the SilenX Ixtrema 400
watt power supply is dead quiet. A person would have to be within 1-2 inches
of the unit in order to hear it. Therefore SilenX is THE power supply for the
HTPC computer enthusiast.
The rear intake area is not completely “filled” by grill slots.
SilenX has shock mounted the fan in order to further dampen noise.
The soft rubber “screws” hold the fan in place and provide a shock
absorber between the PSU case and the fan.
SilenX also features the Molex connectors with finger grips which are great
for assisting in unplugging devices but can be inconvenient for tight areas
such as ATI additional power input connections.
Two SATA headers are on a dedicated line which is preferable. The ATX cable
is sleeved and bound at either end with a rubberized shrink wrap.
SilenX have chosen a larger heatsink design. The heatsink is exactly the same
as in the FSP 400-60PFN except the FSP cuts the heatsink to fit around FSP’s
choice of capacitors.
The ridges of the heatsink provide more surface area to radiate heat which
is then carried away by the exhaust fan. Larger heatsinks are required since
the fan has a much lower CFM.
A thermal probe monitors the heatsink temperature and adjusts fan speed automatically.
The (less than) 14 dBA fan pushes 28 CFM at 2200 RPM. 14 dB is less than whisper
level somewhere around the sound level of rustling leaves. Silent is the best
and most applicable descriptive word for this power supply which makes it perfect
for the HTPC builder.
SilenX also makes the voltage adjustment screw available.
| Volt line | +3.3 | +5 | +12 | -12 | -5 | +5 Vsb |
| Amps | 30 | 32 | 18 | 1.2 | 1 | 2.5 |
| Watts | 99 | 160 | 216 | 14.4 | 5 | 12.5 |
| combined |
240
|
|||||
| combined |
n/a
|
|||||
Zalman also take a FSP OEM product and modify it for a niche market. Zalman
is what SilenX did better.
Zalman was the only review unit that did not sleeve the ATX line.
Zalman also features the largest heatsinks of the comparison group. They are
massive with many fins to provide maximum surface area.
The thermal probe controls fan speed just like SilenX and the voltage adjustment
screw is located immediately below.
Zalman has elected to go with a NMB Minebea 80mm. fan turning at a maximum
of 2700 RPM pushing 31.78 CFM at 28 dBA. This fan does operate at near silent
levels but can ramp up in dB during peak cooling loads.
| Volt line | +3.3 | +5 | +12 | -12 | -5 | +5 Vsb |
| Amps | 28 | 40 | 15 | 0.8 | 0.3 | 2.0 |
| Watts | 85.8 | 200 | 180 | 9.6 | 1.5 | 10 |
| combined |
235
|
|||||
| combined |
380
|
|||||
Test System
- AMD 3200+ 400 FSB
Processor - Gigabyte
7NNXP motherboard - ATI 9800 PRO 256 MB Video
Card Catalyst 3.9 drivers (Application preference ticked for Anti-Aliasing
and Anisotropic Filtering in both Direct 3D and OpenGL, VSYNC disabled BIOS
AGP aperture set to 256) - 2 x 256 MB Corsair PC3200 DDR RAM in DIMM 1 and 3
- LG 52x CD/RW
- 60 GB Maxtor ATA133 Hard Drive
- Samsung 950p 19″ Monitors
- USB Keyboard and Optical Mouse
- Globalwin CAK4-76T HSF
- AMK SX1000
modded PC case (window, fans, cables, loom) - Windows XP Professional Service Pack 1 updated.
The Tests
Tests were monitored by a Fluke 73 Series II multimeter. Readings were taken
on the +3.3, +5 and +12 volt line on the ATX line. Secondary readings were taken
from the +5 and +12 volt lines of a Molex on two separate PSU leads.
Cold start tests were conducted after the system was powered down for one minute.
The lowest voltage was recorded during the process from boot until WindowsXP
was fully loaded.
Operational voltages were recorded after running a two benchmark programs and
a disk defragmenter program. The lowest overall voltage of the three programs
is presented in the database. The lowest voltage was recorded during PC Mark
04 benchmark where all tests were selected and then run. Sisoft Sandra 2004
stress test was executed and the lowest voltage was recorded. (Enable CPU Arithmetic,
CPU Multi-Media, Memory Bandwidth, Cache and Memory, Network/LAN Bandwidth Benchmark)
Microsoft disk defragmenter was executed and the lowest voltage was recorded.
Power factor, kilowatt hours and load and idle watt usage was measured by a
P3 International Kill-a-Watt device. (0.2% accuracy). Aquamark benchmark was
executed at 640×480, 800×600, 1024×768, 1280×1024 and 1600×1200 screen resolutions
at four levels of graphic settings: AA off & details low, AA off and details
high, 16x AA & details low and 16x AA & details high. Sisoft Sandra
file system benchmark was run 5 consecutive times on an 80 GB Western Digital
hard drive with 10 partitions. (Floppy and external drive tests disabled.) The
remaining time after programs completed was inactive and results were recorded
after 6.5 hours from beginning of tests. Overclocked: +1 volt on AGP, DIMM and
CPU voltages and FSB set to 210 from 200 MHz.
Enermax 465P-VE Observations
3.3 V line
There was a 0.01 volt drop during application startup and PC Mark 04.
5 Volt line
A 0.01 volt drop was recorded during video benchmarks of PC Mark 04.
12 Volt line
Voltage dropped to 12.19 volts during Sandra CPU arithmetic tests. CPU loading
during PC Mark 04 also dropped the 12 volt rail to 12.19 volts. MS disk defragmenter
program produced minor fluctuations in voltage.
SilenX Ixtrema 400W Observations
3.3 V line
3.3 volt line was steady through all tests and remained solid at 3.33 volts.
5 Volt line
PC Mark 04 produced a voltage increase of 0.01 volts during tests. Voltage
dropped to 5.32 volts during PC Mark 04 graphic benchmarks. Sandra 04 produced
minor fluctuation up to 5.34 volts. The 5 volt line increased 0.01 volts during
high activity when the system was overclocked.
12 Volt line
There was voltage fluctuation on application startup. 12.18 volts was maintained
through the PC Mark 04 tests. Graphics benchmarks did not tax voltage as much
as file compression benchmarks. MS disk defragmenter caused +/- 0.01 volt fluctuation
from 12.19 to 12.22 volts periodically.
FSP Group Aurora 400-60PNU Observations
3.3 V line
PC Mark 04 produced a voltage reduction of 0.01 volts from baseline during
file decryption benchmark. Sandra arithmetic caused voltage to fluctuate very
briefly up 0.01 volts from baseline.
5 Volt line
MS disk defragmenter program produced an increase in voltage of 0.01 volts
up from 5.06 to 5.07 volts.
12 Volt line
MS disk defragmenter reduced voltage to 12.07 volts. PC Mark 04 reduced voltage
to 12.06 on file compression benchmark. Startup caused fluctuation above and
below baseline. The 12 volt rail fluctuated most out of the test group during
the PC Mark 04 tests. Sandra 2004 produced a voltage drop in the overclocked
state during CPU intensive tests. Application startup caused voltage fluctuations
on the 12 volt rail in the overclocked state. In the overclocked state PC Mark
04 graphic tests produced the most voltage fluctuation above normal of 12.09
to 12.16 volts and then remained at 12.16 volts at conclusion of test and all
tests.
Zalman ZM400A-APF Observations
3.3 V line
No fluctuation in voltage during benchmarks.
5 Volt line
The line increased by 0.01 volts during benchmarks.
12 Volt line
Application startup produced a voltage drop to 11.89 volts. PC Mark held steady
at 11.89 volts. Overclocking the system reduced the voltage to 11.88 volts.
The Zalman 400A was the only tested power supply with readings below 12 volts
on the 12 volt rail.
Comparisons
Leads and available power connectors
| PSU | Leads* | 4-PIN | 3-PIN | SATA | PFC |
| Enermax 465P-VE |
4
|
9
|
2
|
0
|
no |
| FSP Aurora FSP400-60PNU |
4
|
5
|
1
|
1
|
no |
| SilenX Ixtrema 400W |
4
|
6
|
2
|
2
|
Passive |
| Zalman ZM400A-APF |
5
|
6
|
3
|
0
|
Active |
* Does not include ATX, Accessory, 12 volt or
P2 leads.
Length of leads (Centimeters)
| PSU | ATX | Longest | Shortest |
| Enermax 465P-VE |
49.53
|
83.82
|
83.82
|
| FSP Aurora FSP400-60PNU |
54.61
|
68.58
|
48.26
|
| SilenX Ixtrema 400W |
62.23
|
88.90
|
48.26
|
| Zalman ZM400A-APF |
52.07
|
58.42
|
39.37
|
Wattage Comparison (specifications)
|
+3.3
|
+5
|
+12
|
-12
|
-5
|
+5 Vsb
|
+3.3/+5
|
Rated | |
| Enermax 465P-VE |
115.5
|
175
|
396
|
12
|
5
|
11
|
220
|
431 |
| FSP Aurora FSP400-60PNU |
92.4
|
150
|
216
|
9.6
|
1.5
|
10
|
220
|
400 |
| SilenX Ixtrema 400W |
99
|
160
|
216
|
14.4
|
5
|
12.5
|
240
|
400 |
| Zalman ZM400A-APF |
85.8
|
200
|
180
|
9.6
|
1.5
|
10
|
235
|
400 |
Watt/VA Comparison (KillAWatt)
Peak and idle numbers were provided by the KillAWatt device. The KillAWatt
device also provide kilowatt hours and a power factor rating. Less is always
better. The KillAWatt device monitors the watts used by the system including
volt amperes.
|
Watt (idle)
|
VA (idle)
|
Watt (peak)
|
VA (peak)
|
PF
|
KWH
|
|
| Enermax 465P-VE |
160
|
233
|
191
|
271
|
0.68
|
1.05
|
| FSP Aurora FSP400-60PNU |
162
|
252
|
202
|
308
|
0.63
|
1.10
|
| SilenX Ixtrema 400W |
162
|
258
|
202
|
310
|
0.64
|
0.84
|
| Zalman ZM400A-APF |
119
|
188
|
0.97
|
0.91
|
A picture is worth a thousand words but before those thousand words are spoken….know
the question that is being asked.
|
|
|
|
|
|
|
|
Conclusions
It isn’t easy to separate the good from the bad without professional and very
expensive load testers.
All leads were of sufficient length for a Lian Li PC67 (17″ tower), Chenming
(19″ tower) and 24″ server tower. Enermax was the only PSU with
sufficient lead length for a large Lian Li PC70 and 75 tower.
Enermax 465P-VE Conclusions
2 x SATA supported via an included 4-pin Molex adapter. All 4 leads are of
equal length to the first 4-pin Molex connector. All leads are secured with
2 zip ties. ATX lead is braided and Enermax was the only power supply to provide
braid wrap for the P4 and 12 volt lines which included a ninth 4-pin Molex connector.
Cable wraps were well sealed in rubber shrink wrap. Enermax has the longest
length for leads in the test series. There may be too much length for some who
do not practice safe cable management. Enermax also delivered the highest 12
volt rail power.
Enermax is a well known power supply name in the enthusiast community. It is
the trusted “laundry detergent” of power supplies. There is a lot
of brand loyalty to Enermax. There may be equal or better products but many
are hesitant to change because their Enermax power supplies have done no wrong.
Enermax may fall into the middle for price but it is a safe choice and the recommended
choice for those who require longer cable leads.
FSP Aurora 400-60PNU Conclusions
There are only two 4-pin Molex connectors per lead on two of the longest leads.
The third lead has a single SATA power connector. The fourth line features one
4-pin and one 3-pin Molex connector. There was a single zip strap per lead.
The P2 and P4 12V line are without a cable sleeve. The Molex connectors have
the same finger grip as SilenX which is only an inconvenience for video cards
that require 4-pin Molex power. The FSP Aurora has the third shortest leads
of the group. The FSP Aurora has one 3-pin Molex connector. This will only be
a problem for video cards that require the 3-pin connector for additional power
when it is meant for the floppy drive.
The FSP Aurora 400-60PNU is a bargain power supply. It is a bargain not because
it is of cheap construction but because it delivers the best “bang for
the buck”. It is the least expensive of the group by far and has great
modding appeal with the lighted 120mm. fan. It is both quiet and “flashy”.
From the test results there is no reason not to consider this power supply.
SilenX Ixtrema 400 Conclusions
A lead with two SATA connectors is a good idea but having the first at 17 inches
may be inappropriately placed for some users who require more length between
the PSU and the first SATA power connector. The second SATA power connector
is placed at 25 inches (end). The overall cable may be a better at 30 inches
with the connectors placed at 25 and 30 inches from the PSU. The Molex connectors
have a finger grip which is only inconvenient for video cards that require additional
4-pin Molex power. Two zip straps bundle each lead. The SilenX had the second
longest leads in the test group.
SilenX maintained the highest 5 volt rail of the test group and managed to
tie with the FSP Aurora for the least amount of heat. The FSP Aurora fan was
at the lowest setting and would have easily beaten the pack at the highest setting.
The SilenX is recommended overall for buyers looking for one of the most quiet
power supplies around. It is also the most expensive of the group. This PSU
is ideal for audiophiles, recording artists and HTPC enthusiasts as it is nearly
inaudible. The FSP Aurora rivals it at low settings but the bottom fan intake
would make the FSP Aurora totally impractical for desktop cases that HTPC units
are modeled after. The extra dollars would be worth it compared to the Zalman.
Zalman ZM400A Conclusions
The Zalman ZM400A was the only power supply of the test group to be considered
disappointing. There were no SATA headers and no cable sleeve on the ATX line.
The leads will work in a 19″ Lian Li PC 67 case but due to their short
length cable management may be an issue. ANTEC cases do not present a problem
and the short leads may benefit cable management. The Zalman PSU has the shortest
leads of the represented group.
18 dBA is extremely quiet but the power supply controls the fan speed in relation
to temperature. The peak fan noise is 28 dBA which is also very tolerable.
Zalman was the only power supply in the test group to have a less than spec
12 volt rail. The power supply also produced the most heat at the exhaust port.
The Zalman power supply was the only power supply of the test group to produce
system problems. At times the test system would not properly boot and the culprit
is most likely the low 12 volt rail which could be tuned by the user but it
should have been set more accurately at the factory.
Final Words
Is there a clear winner? That depends on what the criteria is. Declaring a
winner requires defining the question. In our forums
nebulous questions are asked which receive nebulous answers. Unfortunately for
one power supply there is a clear loser of this test group and that’s Zalman
even though it used the least KWH. FSP Group may not have a prominent name in
the enthusiast community but we think that it will as word begins to spread.
FSP has the makings of turning the tide on the reputation of “affordable”
power supplies and making their affordable power supply an enthusiasts steal.
Enermax is tried, true and tested and a safe bet and finally there’s SilenX
which is a good niche product with a niche price tag.
It came down to a choice between two power supplies; Enermax and FSP. SilenX
is a “money no object” choice and for those in the quest for quiet
it is the most…sound choice. Enermax has the plethora of Molex connectors,
cable length and a thoughtful inclusion of a 4-pin to dual SATA power adapter.
FSP has a whopper of a 120mm. cooling fan that, surprisingly, doesn’t sound
like a tornado at high speed setting. It is the “coolest” looking
of the bunch.
But as I sat there plugging in the FSP Aurora to imaginary RAID 0 drives, an
ATI 9800 PRO, two optical drives and a floppy I ran out connections. Be it SATA
or 4-pin I was one connector short on the line where I needed it. If the SATA
header on the dedicated line was 4-pin instead and FSP had included a 4-pin
to dual SATA power connector just like Enermax it would have made the world
of difference. Enermax 465P-VE takes the lead when it comes to fulfilling a
lot of connection needs and FSP 400-60PNU takes the lead for price, modder’s
appeal and quiet operation. When you add the cost of extra connectors to the
FSP Aurora 400-60PNU the price difference between it and the Enermax becomes
nominal. Both are our pick but which one for you depends on the question asked
and the configuration you have.
FSP Aurora 400-60PNU
|
Enermax 465P-VE
|
|
Our thanks to Enermax,
FSP Group, SilenX
and Zalman
for their support of this site and many others.
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