Seasonic's Legendary Quality Does Not Disappoint

A Review On: Seasonic Flagship PRIME SERIES SSR-1200PD 1200W PLATINUM FULL MODULAR ATX12V & EPS12V 135mm FDB Fan Super Quiet Power Supply

Seasonic Flagship PRIME SERIES SSR-1200PD 1200W PLATINUM FULL MODULAR ATX12V & EPS12V 135mm FDB Fan Super Quiet Power Supply

Rated # 21 in Power Supplies
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Pros: Power Delivery, Above Average Efficiency, Build Quality

Cons: PCIe Wire Gauge


Over the years Seasonic has built a reputation for offering the highest quality product available, and this new offering is no different. Everything from the packaging to the output load performance screams quality. I will be using this primarily for extreme LN2 overclocking so my perspective in this review is from overclocking usage and not typical gaming usage.

With a Seasonic PSU you get more than the power ratings on the box. They design their PSU’s with unique features that you will come to appreciate.

The most important feature of the PSU, for my particular needs, is that it’s a single 12v rail design. This is critical for extreme overclocking and not all high wattage power supplies use this method. This is one of the features that is easily overlooked but makes a huge difference in the flexibility of use.

  • Model name: SSR-1200PD
  • 80 PLUS®: Platinum
  • Form Factor: Intel ATX 12 V
  • Dimensions: 170mm (L) x 150mm (W) x 86mm (H) +/-1 mm
  • Fan Size: 135 mm
  • Fan Control: Premium Hybrid Fan Control
  • Fan Bearing: Fluid Dynamic Bearing
  • Life Expectancy: 70,000 hours at 40 °C, 15 % – 65 % RH
  • Modularity: Fully Modular
  • Cable type: Flat black cables
  • Operating Temperature: 0 – 50 °C
  • MTBF @ 25 °C, excl. fan: 150,000 hours
  • AC Input: Full Range
  • Protection: OPP, OVP, UVP, OCP, OTP, SCP
  • Safety and EMC: cTUVus, TUV, CB, CCC, BSMI, EAC
  • Environmental Compliance: Energy Star, RoHS, WEEE, ErP Lot 6, REACH

Technical Specifications


The complete package

This is a fully modular PSU, meaning all the cabling you will use is removable from the main PSU. This is a nice feature for a multitude of reasons but in my case I will need the PSU almost completely populated. Having a fully modular PSU in a case allows clean wiring, which is not just pretty it’s functional, allowing more airflow to get to the critical components. While I won’t necessarily use the modular feature, I can certainly appreciate it.


The Prime 1200W with 18AWG cables all around. This is certainly bigger than some of the high wattage budget PSU, but they could have done better. Some of the other top tier competitor PSU’s use 16AWG in places, so Seasonic loses a few points there. The cables do have inline capacitors which is really nice to see.

I am in a unique position to need more PCIe connectors than the average user. Some of the G-Power builds I have done require up to 7 PCIe 8-pin connectors for just one GPU. The 1200W Prime is suited to handle this unique power requirement easily. Here are a few examples of the single GPU PCIe power requirements

HD4850 LN2 EPower V4 Power Card

8800GTX LN2 HOF Power Card

Seasonic takes no shortcuts when it comes to internal construction. The PCB’s are all at least 2 layer, unlike some single layer el-cheapo ones I have seen. The shielding is top tier, soldering is excellent, and the components are of the highest quality.

The only downside is that they left two PCIe connectors unpopulated. On the main modular PCB, there is room for two more PCIe connectors which they chose to not populate for a reason unknown to me.

Overclock testing
One of my main curiosities was to see if I could achieve a higher overclock with a better PSU. For comparison purposes I am using a Rosewill Capstone 1000W Power Supply (80 PLUS GOLD).

Initial overclock test
The goal was to find out if I could use less core voltage to pass the Cinebench R15 with a mild air overclock on my 7700K. To make sure my test results were not skewed in any way I used the exact same bios profile, cooling, and support hardware such as SSD/OS.

I started with the Rosewill PSU and found the lowest voltage required to pass Cinebench R15 at 5.0GHz. I then changed to the Seasonic PSU and repeated the same test. Unfortunately, there was no difference in the voltage required to pass Cinebench R15 between the power supplies.

I next went on to test maximum overclock potential of my 7700K between both power supplies. Ultimately there was no difference in overclocking performance with my 7700K being powered by the top tier Seasonic Prime versus the lower tier Rosewill Capstone.

I attribute the lack of overclock potential difference to the 7700K being too small of a load. The processor I ran the comparison tests with simply does not pull enough current for there to be a difference between two high wattage power supplies.

GPU Overclock test
The goal here was to see if there is a difference in overclock potential with a heavy load. In this case I will be using a GTX480 with an external VRM in form of the brand new EVGA EPower V. The tests were conducted with water cooling but the load is still very heavy for one GPU.

The test scenario for this GPU test was simple. The goal was to see if I would be able to pass 3DMark Vantage with a higher core frequency with GPU powered by the Seasonic PSU vs the Rosewill PSU. Same as with the other tests, I kept environmental variables constant and only changed the PSU.

In this particular, moderately high load GPU test, Seasonic was the champion!!! Simply by changing using a higher quality PSU, I was able to achieve a gain of 20MHz passing core clock.

To see this kind of gain on water is simple incredible. Once the GPU goes subzero and the voltage/power requirements increase exponentially, I would expect to see an even greater difference between each PSU.

Modern overclocking requires top tier products, and Seasonics 1200W PRIME power supply does not disappoint. The build quality is simply amazing, everything has the look and feel of quality right down to the packaging.

As the core count of modern CPU’s goes up, so too does the need for high quality, high wattage PSU’s. My moderate high load GPU tests show that a high wattage rating on the PSU does not tell the whole story. The extremely high load CPU’s that are hitting the market will demand only the best in high wattage PSU’s, and Seasonic is there to fill the need.

Overall I am extremely happy with the 1200W PRIME PSU, it’s easily the highest quality piece of computer hardware I have ever tested. I would have liked to see larger gauge wires for the PCIe, but as I saw myself, the real world tests show that this PSU can handle the load.

Thanks for reading!

1 Comment:

Hmm, $50 less than a silverstone stryder ST 1200w that I bought back in 2008. That's pretty cool. I still want to see a new 90+ efficiency rating though. That old silverstone had the 80 rating, and we're coming up on 10 years. Think its time to roll out a 90 standard.