PSU fans - sleeve and horizontal?

[cegras]

Just as the title says, I've been reading a ton of PSU reviews lately (I love the dissection part) and I notice a lot of quiet PSU's have sleeve bearing fans ... horizontally.

What gives?

[MpG]

Never quite understood that myself, since the real-world duty cycles of PSU fans should be identical to case/heatsink fans. You don't really hear about fan problems in good PSU's, but on the other hand, the gradual degradation of regular sleeve bearing fans is a fairly well-established phenomenon by this point. I can only assume that they've got reason to believe that there won't be any problems within the lifespan of the PSU.