Fortunately my Fortron 600W (single rail) seems to be more stable than it's bigger brother Raider 750W, I can take 48A continuously from 600W while at this amperage most of Raiders 750W died even they are rated 60A for 750W, but 600W is 42A only.
Interesting, I have completely different experiences with Fortron PSU.
All my FSP Fortron Raiders PSU 750W (10units) are working long time ok (each powering 2 units S3+ on default clock), but with all Fortron 600W I had problems...