Is it safe to conclude...

[Slugbait]

Anway, what simple tests can you guys suggest to determine whether his psu is more or less stable and built to last?

It's a Seasonic. Don't waste your cycles on it.

 

[Thor_Odinson]

Was always under the impression that it was a CWT product. Anyway, I'll just have him skip the intensive tests then.

 

[Slugbait]

The non-Enthusiast is CWT. The Enthusiast Series is Seasonic.

 

[bryanl]

that a psu is stable after running smoothly and without issue for 7+ months?

My cousin bought a rig last August with a no-name 650w psu made in China. The reason why he can't go for a Cosair or an Antec was due to budget constraints. Anyway, the aforementioned unit has been powering that GTS 250/Athlon II X4 system every day since it was brought home (and on numerous occasions, even running for 72 hrs straight). He has been using it for both work (architecture) and gaming purposes, so the load is by no means light.

Most likely, the load has been much lighter than 650W, around 200-300W max.

Low quality PSUs tend to contain low quality capacitors that degrade rather quickly and can lose half their capacitance (roughly, the ability to filter rapid voltage fluctuations) in 1-2 years. Many high quality PSUs also contain low quality capacitors.