I wish this was available when I built my HTPC recently!
I look for (in order):
Quality components & assembly (dead PS often causes dead motherboard )
Stable outputs (nothing quite as fun as chasing random problems...)
Quiet (preferably silent)
Modular (much easier to install, and far less cable clutter)
Excellent efficiency at typical idle loads (~100-150W)
So basically, I am looking for a supply almost exactly like the X-560 The only relatively minor change is that 500W max is probably optimum if it helps with cost.
The Main Thing which is obvious is Quality, High Watts Sound Appealing but if its not quality wattage it can hurt you more than help you with overclocking
Stability, efficiency, quiet operation. Seasonic usually has all three of those.
Active PFC is also very nice, as I can plug in wherever.
I could use one of these units to drive a new crossfire rig!
For a PSU, I like to see modular cables, plenty of cables for adding stuff down the road, reliability, clean appearance (raw metal isn't fantastic), and a positive HardOCP review
These Seasonic power supplies seem like quality units... But 560W isn't what I really needed for my next system build. Really wish this was for a unit in the 700W range.
1. Quality components w/ a good warranty.
2. High efficiency (80% gold or platinum)
3. Quiet. I don't want to hear it above my case or GPU fans.
4. Awesome review and passing grade from [H]
5. Price. Doesn't necessarily need to be inexpensive, but must be a great value for what I get.
6. Modular cables
Able to provide actual power as rated, not input power or peak power.
Working OCP and OPP, not just listed as a feature but absent in reality, so it is less likely to burn out itself, and take other components with it.
Non-Single rail, because "trapped amps" is a myth perpetuated by a gross misunderstanding of how power supplies work, and because OCP protection is kind of pointless on a single 100 amp rail. (Think, welder).
Quiet! I mean, I want it to have a quality fan with a quiet ramping profile, assuming it is adequately cooled, which is the installer's job.
Low noise, at least within spec.
Stable voltage, a point many obsess on, but really one of the least important aspects, as long it is within ATX 2.x spec.
Not a ATX 1.x spec power supply with 2.x connectors on it. You know who you are.