Are Seasonic M12 & M12II good PSUs?

[KBD]

Hey guys,

I need a PSU for a build i'm doing for someone based on a e8400 & abit IP35 Pro mobo. I'm looking at these 2 Seasonic 500W modular PSUs, one is an M12 and another is M12II:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151029
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151056

I notice that the M12 version has this in the description: 100,000 hours at 25°C under full load. That's one thing i don't like about it, most PSUs are rated 40 or 50C, this one is only 25C. BTW the M12II version doesn't seem to have this 25C rating.

Anyway, are these good PSUs, and if so which version is better?

[Lemmy]

They are both very good units.
That's actually the MBTF (http://en.wikipedia.org/wiki/Mean_time_between_failures)
If I'm not mistaken, they're actually rated at 50C.

The M12II should be better, since it's a newer unit.

[Quiksilver]

I believe the Corsair HX520 are based off the M12II, I think; not sure.

Also...
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139001
...has $20 MIR.

[KBD]

Yea, i may go with the that Corsair 5120w. though the guy i'm building for wants a solid black PSU with no writing on it like the Corsair. Thnx for answering my question. :)

[Travis]

1. Though maximum continuous output should be rated under 40~50C, MTBF still can be rated under 25C. In fact under higher temperature MTBF derates a lot. See PSU FAQ on BFG Power website for detailed explanations.

2. M12II's design is a bit more efficient than M12 in 300~500W range, but M12 is independently regulated while M12II is group regulated. M12 is based on a performance design. I regard M12II as a "mainstream" design of Seasonic product line, similar to FSP's Epsilon. ("mainstream"=8500GT in video card, higher than entry level but still a low-end part)

3. Corsair HX520/HX620 is based on M12, not M12 II.

[burebista]

I have M-12 500 for almost two years now. What can I say? It's silent, it's reliable and I'm very happy with it.