700W to 850W PSU Group Test

Seasonic M12 700W Modular

Results

The M12 700W Seasonic features four 12V rails which performed very well throughout the testing. There is a high PFC and the efficiency starts from an excellent 83 percent and drops to just a smidgen under 80 percent at full load.

Unfortunately the PSU has a chronic 5V problem which causes it to fail at just 75 percent load and subsequently drop to the lowest recorded setting of 4.42V in the entire group test at full load. Everything else remains fine and in the green, Seasonic just needs to concentrate on the 5V in future.

With just the 12cm fan active, the PSU was exceptionally quiet, quieter than all the other PSUs (as you'd expect from a brand based on silence), but as soon as it hit 100 percent load and the 60mm fan kicked in making it far, far noisier. Seasonic should really have gone with a single larger fan on the top instead to keep it consistently quiet.

Warranty

In addition to the other PSUs, the Seasonic also comes with a three year warranty, of which the first year is return to point of sale and subsequent years it's sent back to Nanopoint UK.

Conclusion

If you're looking not to load it anywhere near 100% load you'll keep it silent and probably with an acceptable 5V as well, but do you really want to spend £130 on a 700W PSU simply not to use anywhere near 700W worth? It's either worth saving the money and going for the better performing Tagan or splashing out a little more on the fuller featured Enermax. It's good and even though you need less 5V and more 12V now, it still fails as a PSU.

Seasonic additionally certifies the product as an 80-plus percent efficiency, and even though it does safely achieve this for the majority of the test, it drops a fraction below at 100 percent load during our tests. In all, this really does not feel like a £130 product. If anything it makes the Tagan and Enermax look like even more bargainous.