Seasonic X-400 Fanless PSU | silentpcreview.com.
The Seasonic X-400 pretty much turn a new page in fanless PSUs. It’s the first one that can run totally without peripheral airflow, ie. it can actually be run fanless. For any other fanless PSU the fanlessness is pretty useless, because you need to add more chassis fans to remove the heat to keep them operating properly.
Still, for most noise-conscious users models like X-650 are more suitable; it runs without fan up to 250W or so and even after that fan runs smoothly and quietly. But for some special applications X-400 for sure fits the bill. It’s quite amazing to have PSU that has MTFB rating of 150k hours – that’s over 17 years, not possible for device with fan.
Another nice thing is that X-400 is the lowest rated 80Plus Gold certified PSU in existence. What makes it interesting is that 400W is pretty much the upper limit for single-GPU gaming machine, if you care about energy efficiency. Because PSUs reach their best efficiency around 50..80% of the maximum rated capacity, single-GPU rig with 650W PSU will spend 95% or more of the time at suboptimal load.
Now I just hope to see 400W X-series with a fan..