Hands On: ASRock Steel Legend SL-1200GW Power Supply

A best-value battle is brewing in high-capacity power supplies, but to understand it we first must consider what makes a power supply valuable: Slowly killing system components before finally blowing up a few years later should rate a power supply’s value at less than zero, so we’ve began our search by first looking at quality certifications, then warranty length and efficiency: Only after we’ve decided that a power supply is worth owning can we determine whether a low price makes it a better value than another, similarly worthy part.

Model	ASRock SL-1200GW (90-UXS120-GFUABA)	InWin P105II (IW-PS-PII1050W)	Sama P1200 (XPH1200-AP)	XPG Fusion 1600 Titanium
+12V Max (Amps)	100A	87.5A	100A	133.3A
12VHPWR	2	1	2	2
6+2 Pin PCIe	3	3	3	6
EPS12V	2	2	2	2
80Plus Cert.	Gold	Platinum	Platinum	Titanium
Weight	1.87kg	1.70kg	1.75kg	2.59kg
Depth	150mm	150mm	150mm	210mm
Warranty	10-years	10-years	10-years	12-years
Price	$150	$200	$158	$500

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The Steel Legend 1200G White finds itself in a particularly fortunate position in that the closest match in our closet, the Sama P1200 White, is currently priced $28 higher than the black version. Both 1200W models feature a standard 150mm depth that’s been around since before ATX was even a standard (as PS/2 for Baby AT builds), giving these the greatest possible chance of fitting into some of the tighter cases that we’ve tested to use the classic bolt pattern.

A second switch labeled “iCool” turns the fan completely off at low temperatures, but we’ll just leave that disabled for our test since cooler units tend to run at slightly greater efficiency. Flipping it over, we find an inner panel with five 8-pin headers to power both EPS12V (ATX12V) and classic PCIe supplemental (graphics card) headers, a pair of 12V-2×6 (PCIe 5.1) connectors that are capable of feeding up to 600W each to 12VHPWR-equipped graphics cards, three headers for drive power cables and a split header pair for feeding the 24-pin EPS/ATX system power cable.

Since the lesser rails are powered via DC-DC conversion from the primary 12V rail, the unit is rated at 1200W combined regardless of whether all of its power is going to 12V connectors or some is being siphoned off by 3.3V and/or 5V devices.

In addition to a single cable to fit each of the mentioned headers, the SL-1200VW includes a quick installation guide, power-on jumper block, AC cable (IEC-C13 to NEMA 5-15P end in USA-distributions), four mounting screws, five hook and loop cable straps, and five zip ties. The jumper block fills jumps the 24-pin connector’s power signal wires to allow the unit to be power cycled without a motherboard, which some builders do when leak-testing or air-bleeding custom liquid-cooling loops.

While the main power cable is plenty long at roughly 60cm (23.6”), the eight and twelve pin cables are even longer at about 64cm (25.2”). Drive power is split between two four-SATA cable and one single-SATA triple-ATA, with about 45cm between the power supply connection and the first drive and 11cm additional distance to each additional connector.

Unlike certain competitors, ASRock applies its own label to the back of the SL-1200GW’s white 135mm FDB (fluid-dynamic bearing) cooling fan, along with part number RL4Z S1352512EH-3M. Its UL component number E154464 indicates Global Fan as the supplier, and ASRock openly discusses the units electrical components coming from HEC (as its ODM).

While we were slightly surprised to find the SL-1200GW’s main component board joined electrically to its power connector board via spade terminals, we still found the power connector board glued to the main component board and decided not to separate those parts. While we can’t see everything, the Infineon Active PFC MOSFETs and Japanese capacitors (most from Nippon chemi-con, a few from Rubycon) indicate a serious effort by the manufacturer to boost the unit’s longevity past its substantial 10-year warranty. 

With the unit’s capacity already verified by both 80 Plus and Cybenetics, we’ll compare its efficiency to our other samples to determine whether it’s the best solution for our legacy motherboard testing platform upgrade:

System Configuration
CPU	Intel Core i9-13900K: 24C/32T, 3.0-5.8 GHz, 36 MB L3 Cache, LGA 1700, Locked at 5.0P/4.0E GHz, 1.25V Core
CPU Cooler	Alphacool Core 1 LT Aurora, Eisbecher D5 150mm, NexXxoS UT60 X-Flow 240mm
Motherboard	ASRock Z790 Taichi Carrara, BIOS 12.13 (04/23/2024)
RAM	Crucial Pro OC Gaming Edition DDR5-6400 32GB Kit
Graphics	ASRock RX 7700 XT Phantom Gaming 12GB OC 2276 MHz GPU, 2599 MHz Boost, GDDR6-18000
System Drive	Crucial T700 PCIe Gen5 2TB M.2 SSD
Test Condition
CPU Load	Prime95 v30.8 build 16 Torture Test, Small FFTs
GPU Load	Furmark 2.7.0.0 GL Test, 1920×1080

The SL-1200GW produced strikingly similar results to the competing P1200, with higher idle power consumption its most noticeable difference.

So which would we pick?

Remembering (from prior reviews) that our use is as a test platform, the overpriced and overcapacity Fusion 1600 Titanium is still in the running. But it won’t fit most of our cases, and we certainly wouldn’t want to pay for it.

ASRock’s SL-1200GW is so close in price, performance and even fitment to the white Sama P1200 that we’d likely choose between these based on price or prior experience with the company’s support network. Right now ASRock has the pricing edge in white, but a discount on the black version of the Sama unit could put it in the builds of anyone who choses the darker color.

ASRock SL-1200GW (90-UXS120-GFUABA)
Pros	Cons
Standard 150mm depth Cybenetics Platinum certified PCIe 5.1 compliant with dual 12V-2×6 Tested 91.2% efficient at 60% load Well priced	Slightly less efficient than closest competitor
The Verdict
Warrantied 10-years by a well-established brand, ASRock’s SL-1200GW is one of today’s best deals in white 1200W power units.

Find it at Amazon

(click for availability)