Best buy 400-450 watts
Among the 400 to 450 watt power supplies in this test there is more choice. A few get disqualified due to unacceptable test results, but there are plenty left.
By far the best PSU in the test is the Seasonic Platinum Series Fanless 400W: extremely efficient, extremely low ripple and passive, so no noise. It's also modular and has enough connectors. It's also the most expensive PSU with an average price of 134 euros.
If you want an affordable modular PSU, there are four options. Out of the Be Quiet Pure Power L8 430W, Cooler Master Silent Pro M2 420W, Corsair CX430M 430W and OCZ Silencer Mk III 400W the OCZ and Be Quiet are the best options when we look at the test results. Both are very quiet, have a very low ripple and are more than 85 percent efficient. We prefer the OCZ due to the better voltages and slightly lower price. 57 euros is a good deal.
If modular isn't important to you, then the Be Quiet Straight Power E9 450W is the best choice. More than 90% efficient, inaudible, and an extremely low ripple. This power supply is so quiet that the much more expensive Seasonic Fanless almost has no added value. But with an average price of 83 euros it's not one of the cheaper options.
Below 60 euros the OCZ Silencer Mk III 400W is the best choice here. Below 55 euros, the previously-recommended Nexus Value 430W remains an excellent choice, in part due to the strikingly low ripple values. The Be Quiet Pure Power L7 430W is a good, but not superior alternative.
Go even cheaper and there's one good 400W PSU left. The Chieftec A-80 400W is the only 400W model that's on average cheaper than 50 euros and performs more than acceptable on all fronts. It's also very quiet.
Seasonic Platinum Series Fanless 400W
Be Quiet! Pure Power L8 430W
Be Quiet! Straight Power E9 450W
PC Power & Cooling Silencer Mk III 400W
Nexus Value 430W
Chieftec A80 400W