Just start to use it a couple of days before, some experience sharing:
1 The PSU is mounted upside as Seasonic suggested. Though there are no any ventilation holes on the top of Solo, some space (~0.5cm) exists between the PSU top and the case.
2 X-400 can be cooled very well in Solo. After 30-minute CPU Burn + GPU Burn (pull 130W AC power on my system), I can hardly perceive any warm when put my hand on the PSU rear (the environment temperature is 22C during test).
3 The air flow of this PSU in Solo is somewhat weird. It pulls fresh air from outside, I use a piece of preservative film to check this, note that the film sticks the PSU in below picture.
4 Though X-400 cools itself very well, the overall system temperature is actually degraded comparing with my previous PSU Antec EA-380 (3~10C for different components). See another thread (http://www.silentpcreview.com/forums/viewtopic.php?t=60171
) for temperatures.
5 During CPU Burn+GPU Burn, I can hear very faint buzz noise if I press my ear on the PSU. It's not perceivable with several cm distance.
[UPDATED on 2010/09/27] Previous description is not true, the buzz noise can be a real problem for this fanless PSU. (1) I can hear the buzz noise from 10-cm away, sometimes it becomes a very annoying high frequency noise which is even more noticeable than rear fan noise (800rpm Noctua S12). (2) Even after system shut down (PSU is not off), the buzz noise still exists and can be clearly heard if close enough. At this time, the system pulls only 1~2W AC power.
I will check this with other X-400/460 owners.