Another question I have is: will the 400W unit stay in production after the introduction of the 800W unit? HDPLEX stopped making the 300W unit when the 400W was released. I wish the 300W version was still in production with upgraded components to remove the coil whine. It is smaller than the 400W with its smaller heat sink and thus can fit in tighter spaces. Or am I wrong in this statement?
The 800w unit is not a replacement for the 400w. The 400w is the current flagship product for us SFF enthusiasts. The 800w unit is literally two 400 units on one board, and is intended for industrial applications. This doesn't stop us from using it in weird builds, but it requires two DC inputs in order to utilize 800w.
The 300 and 400 are identical in size save for the length--the 400w is 10.5mm longer. The 800w unit is much larger than the current 400w.
The 400w DC is about as perfect as it gets right now. It runs cool, quiet, and it can peak at 460 and hold peak for about 30 minutes before thermal shutdown. It can run at 400 continuous with very low electrical noise.
The 400w AC is an incredible product and I have NO reservations about recommending it, but it will have to go through a couple revisions to be perfect, I think, but that will happen naturally over time like any product. Right now it is much, MUCH better than I was even hoping for.
Peace