Lian Li SX1200P Platinum PSU Review

1. Introduction2. Bundle & Cabling3. External4. Internal5. Testing Methodology and Results6. Closing Thoughts7. View All Pages

Today we take a look at one of the latest power supplies from Lian Li, the SX1200P. This fully modular, Platinum-rated unit supports ATX 3.1 and PCIe 5.1 standards and is supported with a 10-year warranty. It ships with high-grade Japanese capacitors and will suit a variety of smaller chassis due to the compact 140mm depth. Is the SX1200P worth the asking price of $160? We find out today.

Lian Li offer three wattage options in this range – 850W, 1000W and the 1200W model we are looking at today. They also offer them in white and black colour schemes. Right now, while Lian Li say they have 80 Plus Platinum certification, they have not supplied me with any Cybenetics certifications and they are not on the box or included in the literature either. They told me they are working with Cybenetics on certification for this unit, but at the time of press we don't have any details.

Product Features:

• 80 Plus Platinum Rated.
• ATX 3.1 and PCIe 5.1 compatible.
• 100% Japanese 105C Capacitors
• 12V-2×6 High Current Copper Alloy Terminals
• Braided Texture Cables with Cable Combs.
• 120mm Fluid Dynamic Bearing Fan.
• Single +12V rail.
• 10-Year Warranty.

The Lian Li SX1200P arrives in a box with a high resolution image of the power supply on the front. We did get a white version of the unit, so I wonder if Lian Li have two boxes for each colour. The front of the box highlights key features, such as ATX 3.1, PCIe 5.1, 80 Plus Platinum certification and the 10-year warranty terms.

The rear of the box focuses on a small list of features in multiple languages and two images of the cables.

Inside the box there is some literature on the power supply, and the unit itself is shipped between two soft pieces of foam. A white power cable is placed beside the cable bag. Lian Li also include some white cable ties, cable combs and mounting screws.

The Lian Li cables are all individually sleeved. In the image above, the cables at the bottom are all a slightly different tone to the ones above which is unusual to seef

The SX PSU is shipped with 3x PCIe 6+2 cables, while the 1000W and 1200W models ship with two additional 12V-2X6 to 2x PCIe 6+2 pin cables. This means they can power accessories from Lian Li as well, such as the Universal USB and PWM Fan Hub, as well as other add-in components.

The MB 20+4 pin cable is 16-22 AWG, the CPU 4+4 pin is 16 AWG, the GPU 12v-2×6 (600w) cable is 16 AWG and the SATA cables are 18 AWG.

Lian Li sell these units in both white and black. The white unit is nicely finished and looks great. It measures 140mm x 86mm x 150mm (DxWxH).

The fan grille on this unit is epic. Initially I thought it was damaged in transit, but i took the second image above to try and highlight how Lian Li have designed the grille to run at different height angles. I don't think I have ever seen this before with a power supply.

The power side of the supply is home to a power connector socket, a power switch and a zero fan mode switch. Lian Li don't actually call it a ‘zero fan mode switch' as they refer to it with the purist term of ‘fan ON/OFF'. Basically their internal graphs show that in ‘fan OFF' mode, the fan is disabled completely until around 400 watts when it will switch itself on. This will ensure that in lower power demand situations the fan will remain disabled, lowering noise output.

The modular side of the unit is split into two rows, all clearly labelled for ease of use during the installation phase. The 12V-2×6 socket is coloured a little differently top left in the image above.

The unit is able to deliver 100A on the primary +12V rail, and 20A on both +3.3V and +5V rails. Total output is 1200W.

Lian Li are using a Hong Hua HA1225M12F-Z fan – this is a commonly seen fluid dynamic bearing (FDB) fan in high end units, such as those from Seasonic. It is rated 12V and 0.45A. This fan can rotate to a maximum speed of just over 2,000rpm.

The OEM for this power supply is Zhong Yuan Power, not an OEM we see very often in our testing. This is a half bridge design with an LLC resonant converter featuring synchronous rectification – generating the minor rails via DC-DC converters. They are using a high-grade 105C-rated Capacitor from Nippon Chemi Con in the primary stage, rated 420V 1010uF. Other capacitors in the unit are from Rubycon as well.

Soldering quality is decent, and the overall build quality seems ok on the main PCB. Over Power Protection (OPP), Over Voltage Protection (OVP), Short Circuit Protection (SCP), Over Current Protection (OCP), Over Temperature Protection (OTP), Under-Voltage Protection (UVP), Surge and Inrush Protection (SIP), and No Load Protection (NLP) are all included.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 Watt DC load.

We test ambient temperatures at 35C in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:

• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
120W	0.90	3.34	0.93	5.02	8.94	12.06	0.50	5.00	0.20	-12.02
240W	1.63	3.34	1.63	5.02	18.45	12.05	1.00	5.00	0.20	-12.01
600W	3.00	3.33	3.12	5.02	46.76	12.03	1.50	5.00	0.30	-12.02
900W	4.02	3.33	4.07	5.02	70.84	12.02	2.00	5.00	0.30	-12.01
1200W	5.02	3.33	5.20	5.02	94.58	12.00	2.50	5.00	0.30	-12.01

Load regulation is very good across the rails.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
1190W	4.0	3.34	3.0	5.02	88.0	12.01	0.2	-12.01	0.50	5.00
240W	19.0	3.33	22.0	5.01	2.5	12.06	0.2	-12.02	0.50	5.00

The SX1200P handled our cross load tests without any issues. When hit with 88A, the +12V rail held at 12.01.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum. ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
100W	6	9	7	8
200W	9	13	9	9
400W	11	15	12	11
600W	15	18	15	12
800W	17	21	18	13
1000W	19	23	22	15
1200W	22	28	26	17

This unit passes our ripple suppression tests without any issues. The results are pretty good, if not class leading. +3.3V and +5V rails peak at 22mV and 28mV respectively. The primary +12V rail peaks at 26mV at full load.

Efficiency (%)
100W	87.5
200W	92.2
400W	93.3
600W	94.2
800W	93.8
1000W	93.3
1200W	92.7

Efficiency is good overall, hitting around 94% at peak. This drops to 92.7% at full load. These are Platinum efficiency levels.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the power supply we have taken it into our acoustics room environment and have set our SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings with real world situations to help describe the various levels.

KitGuru noise guide

10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refrigerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
100W	<28.0
200W	<28.0
400W	<28.0
600W	31.9
800W	33.7
1000W	37.1
1200W	38.8

Lian Li are using a quality fan in this unit and under most circumstances it is pretty quiet. It is unlikely you will hear it operating with some case fans in the build. When you task it with over 1000 watts it becomes audible, hitting a maximum noise level of around 39dBa at full load.

Temperature (c)
	Intake	Exhaust
100W	35	38
200W	36	41
400W	38	44
650W	43	47
800W	45	53
1000W	47	56
1200W	50	59

The efficiency of this unit combined with the quality FDB fan ensure temperatures are well maintained at all times.

The Lian Li SX1000P is quite an impressive power supply, while the choice of white and black models will also appeal to a wide audience. Finishing quality on the external unit is very high and I especially like the various height angles of the top mesh panel. I don't think I have ever seen that before. It is subtle but effective.

Lian Li are working with OEM Zhong Yuan Power for this unit and likely the 850W and 1000W in this range as well. While this is not a company we see very often, they are more of a background operation, rather than a front facing manufacturer like Seasonic or CWT. They are a Chinese outfit that have built their own units for brands such as Darkflash in the past.

Technically the unit performed well. Load regulation was very tight and it handled the cross load test without a problem. The adoption of high-grade Nippon Chemi Con and Rubycon capacitors in the primary and secondary stages helps reassure that it is a serious design. The primary 105C-rated Nippon Chemi Con capacitor is powerful @ 420V 1010uF.

I appreciate that they opted to include a high-grade Hong Hua fluid dynamic bearing fan in the unit, these are good fans we have seen in products from other leading brands such as Seasonic and DeepCool. Under most load situations it remains inaudible, or almost inaudible, and only at close to full load will you hear it operating.

I was a little surprised that this unit didn't ship with Cybenetics certifications on the box, and when I enquired with Lian Li about this, they said they were currently working with them to get certifications. The unit currently has 80 Plus Platinum certification, and we hope Lian Li will update their data if and when Cybenetics give them approvals.

The price of this unit is very competitive, considering this is a 1200W Platinum rated PSU. At the MSRP of $159.99 it delivers great value for money. The 850W and 1000W versions will be priced at $119.99 and $149.99, respectively. We currently don't have any links or pricing yet for Europe or the UK, but we could imagine this product will cost around £150 in the UK and a similar amount in euros.

All in all, Lian Li have delivered a quiet, high wattage 1200W power supply that uses premium Japanese capacitors and delivers stable power at Platinum levels of efficiency. It is fully modular, well put together and is competitively priced with a 10-year warranty. It goes without question it should be on your final shortlist for a new system build.

Pros:

• Fully modular.
• PCIe 5.1 and ATX 3.1 compliance.
• Platinum levels of efficiency.
• White and black colours available.
• 105C-rated Japanese capacitors from Nippon Chemi Con and Rubycon.
• Quiet fluid dynamic bearing Fan.
• Ripple suppression is good.
• Load regulation is tight.

Cons:

• A lot of competition in this sector.
• Availability will likely be a problem in various countries (for a while at least).

KitGuru says: The Lian Li SX1200P delivers high-grade power at Platinum levels of efficiency. It is fully modular, quiet and the quality of the modular cabling is super. With a 10-year warranty, we rate this product very highly.

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