### Lian-Li Silent Force 750W Review

paulktreg - 2008-09-29 13:16:09 in Power Supplies
Category: Power Supplies
Reviewed by: paulktreg
Reviewed on: October 7, 2008
Price: \$195.00

## Introduction:

If you are in the market for a new power supply then consider helping conserve the planet and its already stretched energy resources by choosing an energy efficient unit that meets the requirements of the 80 Plus program. Power supply efficiency is improving all the time and 80 Plus certification (usually) guarantees you a minimum 80% at all loadings.

For those of you unfamiliar with efficiency and how it is calculated, here’s a brief explanation. Power is measured in Watts (W), Voltage in Volts (V) and Current in Amps (A). Watts = Volts X Amps or W=V*I. (Strictly speaking it's w=v*i lower case. Why i for current? I guess it's because A is used for something to do with magnetic stuff in SI units. We digress). Power supplies are rated by the maximum DC output power available in Watts. This power is distributed across the 3V3, 5V, 12V, -12V and 5VSB. You will usually find all the information you need on the power supply specification label.  Pay attention to the combined maximum powers for “groups” of rails. Your power supply may, for example, have 20A available on each of four 12V rails. That gives you (12X20x4=) 960W total available on the 12V rails right? Wrong! There will be a combined maximum limit that will be in the region of 600W to 700W for this example, so beware. The combination rule may also apply to the  3V3 & 5V0 rails, the 3V3, 5V & 12V rails and I have even seen maximum combined limits for the -12V & 5VSB rails, so read the specification label carefully. (This power supply specification label gives a fine example). My DC output power is found by measurement and will be a total of the individual V*I values for all connected rails to give us DC Watts Out. To get the DC output, the power supply needs to convert the AC input. If we know the AC supply voltage and the AC current drawn by the power supply (safest way to measure this would be to use the Kill-O-Watt meter or similar) then the AC input power in Watts=V*I. Efficiency is then calculated by dividing DC Power Out by AC Power In. Efficiency= DC Watts Out/AC Watts In. If you want the result as a percentage, simply multiply this value by 100.

This time around I am going to be testing an 80 Plus certified power supply from Lian-Li. Probably better known for their high quality PC cases, the Silent Force series is their latest offering in the enthusiast power supply market. The Silent Force power supply has three variants, 650W, 750W and 850W models. I will be looking at the 750W this time around.

The ever increasing demand of power users for high-end products and outstanding performance has initiated Lian Li to announce a new series of Power Supply Units (PSU) called the “SILENT Force”. Building from Lian Li’s reputation as an enthusiast brand catering to the ultimate tastes, the product features a 135mm ball-bearing fan, modular cable management, and Japanese Main Capacitors to ensure that the quality and standards, as well as durability of Lian Li products is as outstanding as our customers expect.

With clean and stable power driving your PC via the SILENT Force PSU and the multi 12V rails output and bead core protection for the PCI-e connectors, failsafe safety protections, and 80 Plus output all combine to give the SILENT Force PSU superior durability than anything else you are likely to get. SILENT Force PSU’s have today what PC power user’s need tomorrow!”

## Closer Look:

The Lian-Li Silent Force 750W power supply is packaged in a plain black box with a thin card sleeve for all the necessary information. I can only presume that the internal box is used across the range of power supplies with a different sleeve. The information is well laid out and unclutterd and all sides are gloss black except the back panel. The front gives you an obligatory power supply photograph, which I have to say is top quality and model and product name and the Lian-Li logo. The bottom left hand corner contains a sticker with the power supply wattage and model number which wraps around to the side to attach the sleeve and give you the same information on the side panel. The back of the power supply sleeve gives you the rather lengthy features list, the more information the better I say provided the layout remains tidy. On the left hand side we are treated to a series of icons depicting some of the major elements from the features list.

The side panel below gives you small photographs of all the power supply connectors and a table of the named connector types and quantities. A welcome addition on the top is the inclusion of a sturdy carrying handle.

The wrap around sticker on the left and an adhesive specification label on the right. The side panel also informs us that the power plug is suitable for the EU. I have to ask - why they didn't send me a UK version?

Lift the lid and the Silent Force 750W is neatly enclosed in foam. User manual in the side space along with a black canvas bag containing all the cabling resting on top of the hard wired power supply cables neatly tied with a wire wrap.

A sneak preview of the power supply along with the user manual and cable bag. The bag is on the large side and contains all the modular cables, power cord and a small plastic bag containg four mounting screws.

This is one of the best looking packages I've seen. The information is useful and well laid out and all the illustrations are top quality and informative. Let's hope the power supply performs to the same high standard.

## Closer Look (The Power Supply):

The Lian-Li Silent Force 750W certainly looks the part. I especially liked the black textured finish to the paint work, probably because it's different. The back of the power supply as a large honeycombed grill, power inlet and a nice large power on/off switch. Have you ever struggled with your hand round the back of your PC trying to find the small rocker switch that most manufacturers insist on fitting? This one should be easier to find! A very nice inclusion is the label telling you what voltages are available on the modular cable connectors and which 12V rails they are connected to (in this case 12V3 and 12V4). Not only does this help me know were to connect the loads, it helps you the installer find the correct connection points for your hardware.

The standard specification label is attached to one side and on the other we are informed of the Fan Delay-Off Function. I could not get this to work on the last power supply that included this function so let's hope I have better luck this time.

The next two photographs show the sleeved hard wired and modular cables. You will notice the inclusion of a plastic sheathed ferrite bead at the power supply end of the cable on the two PCI-E power cables in the center of the photograph. These are normally fitted to help reduce EMI (electromagnetic or radio interference) on the power rails and this is the first power supply I have seen with these fitted. I have to question the inclusion of this component but unfortunately I have no valid way of testing their effectiveness.

The Lian-Li Silent Force 750W is fitted with a large 12V DC 135mm clear plastic ball bearing fan manufactured by Globe and covered by a black, slightly metallic, painted grill. If you look carefully at the internal view of the fan on the right you will see the inclusion of slightly fogged, plastic baffle, to optimise airflow over the internal printed circuit board and heatsinks for maximum cooling effect.

The internal layout ot the power supply is uncluttered which should maximise airflow over the components. The copper coloured heatsinks have a fine toothed surface to increase the surface area of the heatsink and improve heat dissipation.

The view below shows more notches cut into the heatsink to further increase the overall surface area. In the photograph above you can see a sheet of insulator material, also fitted to the otherside of the power supply (I have folded it down to take the photograph) to prevent any shorts to the earthed power supply casing.

The main capacitor is made by Nippon Chemi-Con of Japan and in case you forget this, there is a MIJ label stuck to the top of the main capacitor proclaiming these components are of Japanese origin. All the electrolytics, on which I could make out a manufacturers mark, are Japanese in origin and rated at 105°C, rather than 85°C, which will improve the lifespan of the power supply.

A well built unit containing what would appear to be quality components. I am very impressed with overall quality of this power supply so far, let's hope the electrical performance is up to the same high standard.

## Specification:

Ratings Table:

 Model No. Lian-Li Silent Force 750W (PS-S750GE) AC Input 100-240VAC    10A    50/60Hz DC Output +5V0 +3V3 +12V1 +12V2 +12V3 +12V4 -12V +5VSB Output Current 30A 28A 18A 18A 18A 18A 0.8A 3A Maximum 180W 650W 9.6W 15W Combined 725W 25W Wattage 750W

System Protection:

No specific figures are given for the over current/voltage/power protection/temperature, under voltage protection or short circuit protection. The only information given is in the features list and a short paragraph in the user manual.

Safety & Agency Approvals:

• Underwriters Laboratory USA & Canada
• TUV Germany
• FCC USA
• CE European Union
• CB

Power Supply Weight:

 Power Supply Weight Manufacturer/Model Weight Lian-Li Silent Force 750W 2.1kg 4.6lbs

Power Supply Connectors:

 Lian-Li Silent Force 750W Connectors 24 Pin Motherboard Hard Wired 1 EPS12V 8 Pin Hard Wired 1 P4-12V 4 Pin Hard Wired 1 Molex 4 Pin Modular 4 SATA Power Modular 6 FDD 4 Pin Power Modular 2 PCI-E 6 Pin Modular 2 PCI-E 6+2 Pin Modular 2

## Features:

There are quite a few features on the back of the packaging, under three different headings, here they are:

Performance Features:

• Up to 85% efficiency & low power consumption
• RoHS ready and environmental friendly
• 3.3V DC to DC VRM layout design to enhance stability and efficiency
• Double forward converter design for highest efficiency and best stability
• Active power factor correction (>0.99%), reduce line loss & power distribution
• MTBF > 100,000 hours
• High reliable Japan made main capacitors, increase product life & reliability
• Tuned for best silence performance
• Dual magnetic amplifiers, improve cross regulation tolerance on +12V rails in 3% for optimized stability
• Bead core protection on PCI-E connectors to minimise EMI for reducing noises

Flexibility Features:

• Complies with the latest ATX 12V V2.3 & EPS 12V V2.91
• Supports Intel dual and quad core CPU
• Supports AMD dual and quad core CPU
• Supports SLI and Crossfire Multi-GPU graphics card (PCI-E 2.0 Compliant)
• Easy swap connector for easily & quickly unplugging
• Universal AC input (full range), plug & run safely at 90-240VAC
• Short circuit protection (SCP), over voltage protection (OVP), under voltage protection (UVP), over current protection (OCP), over temperature protection (OTP) and over loading protection (OLP) for your hardware safety
• Cable management increases airflow, better cooling performance

Silence Features:

• 135mm ball-bearing cooling fan, increases airflow, better cooling performance, reduces rotation speed and noise level (17dBA)
• Ultra ventilation design, honey comb vent for minimized airflow resistance for maximum cooling
• Smart & silent fan control, thermal control to balance noise and cooling
• Sleeve cable for minimized airflow resistance for maximum cooling

Lian-Li certainly get the prize for the longest feature list so far!

## Testing:

Electrical Safety:

 Electrical Safety Test Class 1 Manufacturer/Model Pass/Fail Lian-Li Silent Force 750W Pass

Short Circuit Protection:

I short circuited the 3V3, 5V0 and all four 12V lines in turn. The power supply did shut down, and once the short was removed and the unit switched off for at least one second, resumed normal operation. Although listed here at the beginning of the testing section, I tend to leave this test until the very end, in case it doesn't quite go to plan.

Testing @ 110VAC

 110VAC - Total Load at 176W which is 23% of Rated Maximum Output Power. PSU DC Line Measured Voltage(V) Measured Current (A) Load Power (W) ATX12V V Limits (V) Pass/Fail +3V3 3.38 3.16 10.68 3.135 – 3.465 Pass +5V0 5.11 4.78 24.43 4.75 – 5.25 Pass +12V0(1) 12.18 2.57 31.30 11.4 – 12.6 Pass +12V0(2) 12.19 2.58 31.45 11.4 – 12.6 Pass +12V0(3) 12.18 2.55 31.06 11.4 – 12.6 Pass +12V0(4) 12.18 2.60 31.67 11.4 – 12.6 Pass -12V0 11.90 0.36 4.28 10.8 – 13.2 Pass +5VSB 5.03 2.16 10.86 4.75 – 5.25 Pass Total Power Supply Loading 176W

 110VAC - Total Load at 476W which is 64% of Rated Maximum Output Power. PSU DC Line Measured Voltage(V) Measured Current (A) Load Power (W) ATX12V V Limits (V) Pass/Fail +3V3 3.33 7.91 26.43 3.135 – 3.465 Pass +5V0 5.07 9.40 47.66 4.75 – 5.25 Pass +12V0(1) 12.11 7.79 96.52 11.4 – 12.6 Pass +12V0(2) 12.11 8.02 97.12 11.4 – 12.6 Pass +12V0(3) 12.08 8.03 97.00 11.4 – 12.6 Pass +12V0(4) 12.08 7.99 96.52 11.4 – 12.6 Pass -12V0 12.19 0.37 4.51 10.8 – 13.2 Pass +5VSB 4.94 2.15 10.62 4.75 – 5.25 Pass Total Power Supply Loading 476W

 110VAC - Total Load at 748W which is 100% of Rated Maximum Output Power. PSU DC Line Measured Voltage(V) Measured Current (A) Load Power (W) ATX12V V Limits (V) Pass/Fail +3V3 3.28 12.21 40.05 3.135 – 3.465 Pass +5V0 5.06 9.40 47.56 4.75 – 5.25 Pass +12V0(1) 12.05 13.40 161.47 11.4 – 12.6 Pass +12V0(2) 12.02 13.47 161.91 11.4 – 12.6 Pass +12V0(3) 11.96 13.45 160.86 11.4 – 12.6 Pass +12V0(4) 11.97 13.44 160.88 11.4 – 12.6 Pass -12V0 12.56 0.39 4.90 10.8 – 13.2 Pass +5VSB 4.83 2.12 10.24 4.75 – 5.25 Pass Total Power Supply Loading 748W

Testing @ 230VAC

 230VAC - Total Load at 176W which is 23% of Rated Maximum Output Power. PSU DC Line Measured Voltage(V) Measured Current (A) Load Power (W) ATX12V V Limits (V) Pass/Fail +3V3 3.38 3.15 10.65 3.135 – 3.465 Pass +5V0 5.12 4.78 24.47 4.75 – 5.25 Pass +12V0(1) 12.18 2.57 31.30 11.4 – 12.6 Pass +12V0(2) 12.19 2.58 31.45 11.4 – 12.6 Pass +12V0(3) 12.18 2.55 31.06 11.4 – 12.6 Pass +12V0(4) 12.18 2.59 31.55 11.4 – 12.6 Pass -12V0 11.88 0.36 4.28 10.8 – 13.2 Pass +5VSB 5.10 2.18 11.12 4.75 – 5.25 Pass Total Power Supply Loading 176W

 230VAC - Total Load at 477W which is 64% of Rated Maximum Output Power. PSU DC Line Measured Voltage(V) Measured Current (A) Load Power (W) ATX12V V Limits (V) Pass/Fail +3V3 3.33 7.94 26.44 3.135 – 3.465 Pass +5V0 5.07 9.42 47.76 4.75 – 5.25 Pass +12V0(1) 12.10 7.99 96.68 11.4 – 12.6 Pass +12V0(2) 12.11 8.04 97.36 11.4 – 12.6 Pass +12V0(3) 12.08 8.04 97.12 11.4 – 12.6 Pass +12V0(4) 12.08 8.02 96.88 11.4 – 12.6 Pass -12V0 12.20 0.37 4.51 10.8 – 13.2 Pass +5VSB 4.94 2.15 10.62 4.75 – 5.25 Pass Total Power Supply Loading 477W

 230VAC - Total Load at 748W which is 100% of Rated Maximum Output Power. PSU DC Line Measured Voltage(V) Measured Current (A) Load Power (W) ATX12V V Limits (V) Pass/Fail +3V3 3.27 12.26 40.09 3.135 – 3.465 Pass +5V0 5.00 9.43 47.15 4.75 – 5.25 Pass +12V0(1) 12.02 13.42 161.31 11.4 – 12.6 Pass +12V0(2) 12.02 13.49 162.13 11.4 – 12.6 Pass +12V0(3) 11.96 13.46 160.98 11.4 – 12.6 Pass +12V0(4) 11.97 13.48 161.36 11.4 – 12.6 Pass -12V0 12.55 0.39 4.89 10.8 – 13.2 Pass +5VSB 4.83 2.12 10.24 4.75 – 5.25 Pass Total Power Supply Loading 748W

The DC voltage regulation of the Lian-Li Silent Force 750W is excellent. I was able to take the power supply to 100% of the rated load and the power supply held the rails well within the ATX12V specification, the primary 3V3, 5V0 and particularly the 12V rails are almost perfect.

## Testing (Continued):

Efficiency and Power Factor:

 Output & Efficiency at 110VAC DC Load (W) AC Load (W) PF Efficiency (%) Pass/Fail 0 7 0.56 N/A N/A 176 222 0.95 79 Pass 476 596 0.98 80 Pass 748 976 1.00 77 Pass

 Output & Efficiency at 240VAC DC Load (W) AC Load (W) PF Efficiency (%) Pass/Fail 0 2 0.18 N/A N/A 176 218 0.84 81 Pass 477 573 0.91 83 Pass 748 950 0.94 79 Pass

The efficiency of the Lian-Li Silent Force 750W, although very good, did not quite meet the requirements of the 80 Plus certification. I think I can allow one or two percent either way (my test equipment does after all have some measurement inaccuracies in the order of a few percent), but feel I must give a fail (for 80 Plus) at 748W on 110VAC. It is very close and if I was to test another Silent Force 750W, it could very well pass. The power supply did however meet the recommended efficiency ratings of the ATX12V specification and gets an overall pass in this section.

Power factor must be maintained at greater than 0.9 for 80 Plus certification and as you can see we have a low value of 0.84 at 176W on 240VAC. I must give the power supply a definate fail for this minor discrepancy.

AC Ripple On DC Outputs:

Ripple/noise levels at 110VAC and 230VAC are virtually identical (slightly lower at 110VAC if anything, which is to be expected) and I have therefore included screenshots and values for  230VAC only.

AC Noise/Ripple on 3V3 rail.

AC Noise/Ripple on 5V0 rail.

AC Noise/Ripple on 12V rail.

 Lian-Li Silent Force 750W AC Ripple/Noise Measurements DC Output 3V3 5V0 12V1 12V2 12V3 12V4 -12V 5VSB Ripple (mV p-p) 8 14 32 32 32 32 42 15 Pass/Fail Pass Pass Pass Pass Pass Pass Pass Pass

No problems. The Lian-Li Silent Force 750W produces very clean rails with ripple/noise levels well below the maximum permissable levels.

## Testing(Continued):

Temperature, Noise Levels and Fan Speeds:

I am not going to give a pass or fail in this section, as the ATX12V V2.2 specification does not really have any references on which to base a decision.

Temperatures are purely for information only, as there are too many variables involved when installed in a case, which, by the way, it wasn't. Ambient temperature, processor cooling heatsink/fan efficiency and case cooling fans all play their part on the temperature of the air entering the power supply, and consequently the temperature of the air leaving it. No valid conclusions can be made from this test. I imagine we could be talking an extra 10 or 15°C on my Temp In figures, giving a maximum out of somewhere in the region of 50°C at full throttle?

 DC Loading Temp In (°C) Temp Out (°C) Δ Temp (°C) Fan Speed (RPM) 176W 21.1 32.6 11.5 764 477W 22.3 37.1 14.8 1035 748W 21.4 42.0 20.6 1336

The Lian-Li Silent Force 750W does live up to its name and remains very quiet even when the 135mm fan runs at 1336 RPM. This maximum speed is not fast when compared with other power supplies in its class but does appear to keep the power supply cool at all times. Perhaps the inclusion of the baffle, mentioned earlier, does improve air flow and cooling.

The "Fan Delay-Off Function" that I talked about earlier does indeed work. The power supply ran for approximately 3 hours at maximum loading and at shut down (using the motherboard on/off signal via the green cable), the fan continued to run at 720 RPM for approximately 2 minutes. Cooling down the power supply at PC shutdown like this will I'm sure prolong the life of the power supply but not by any significant amount I'm sure.

## Conclusion:

Environmental Factors:

No prizes for the packaging I'm afraid. The use of a cardboard sleeve for the box and a large foam envelope for the power supply do nothing for the environment. We again also have the black canvas type bag, probably plastic based, it's nice to have but is it really necessary as we can all find somewhere safe to store the unused modular cables. The high efficiency and power factor do however pull it a few points back. Thought for the day. Does the inclusion of the box carry handle mean one less plastic carrier bag fluttering from the branches of the nearest tree?

Price Per the Watt:

Power Supply Lian-Li Silent Force 750W at \$195.00 = \$0.26/Watt (October 2008)

The Lian-Li Silent Force 750W comes with an excellent set of modular cables that will provide all of the connectors you are likely to need and more. The inclusion of a ferrite bead on the PCI-E power cables to reduce radio frequency interference is unusual but is it needed? Unfortunately I have no way of testing the effectiveness or usefulness of this feature but they certainly won't do any harm. The user manual is adequate and will provide all the information you are likely to need. One useful inclusion is pin-out diagrams for all the connectors along with the voltage and cable colour at each pin .

I can't help wonder why Lian-Li chose the slightly textured black paint finish for this power supply. Renown for their brushed aluminium PC cases, why not do a power supply to match? Perhaps they are catering for the masses.

The Lian-Li Silent Force 750W will provide what most PC users want, stable rails with low noise, up to its rated maximum power. The efficiency, although very good, is borderline as far as 80 Plus certification is concerned and at one point we get a power factor that dips below the required level of 0.9. If efficiency and power factor aren't top of your list of requirements then this power supply will easily run all dual graphic card configurations with ease and is on par with other power supplies in its class. I can't keep giving gold awards to every power supply that I test so, due mainly to some minor hiccups in efficiency and power factor, this one easily merits a OCC Silver Award.

## Pros:

• Excellent DC voltage regulation
• Excellent DC quality
• Active PFC
• MTBF>100,000 hours
• All Japanese capacitors
• Quiet cooling fan

## Cons:

• Borderline 80 Plus
• Uncertified for SLI