For me, the best raisers are VER 006 (molex). I connect them from the power supply and they work reliably.
I read the topic about raisers - video card killers
https://miningclub.info/threads/rajzery-ubijcy-ubivajut-vidiki.34995/that's why I don't buy 6 pin raisers.
But my graphics cards don't use more than 150 watts.
If you are using 3080 or 3090 then it is better not to use molex
I google translated the Russian article.
from the link above
"I hope this topic will save at least some video cards, in my case 10pcs. gone to the other world
Link to the riser
https://ru.aliexpress.com/item/4PIN...32848384892.html?spm=a2g0s.9042311.0.0.fxJDKRThe idea is not bad, these risers use a DC-DC converter to generate 3.3V from an input 12V. DC-DC has a higher efficiency than linear regulators
BUT! As it turned out, it was in THIS batch that defective risers came from this seller! Out of 24 pieces, 18 pieces are faulty and with almost 100% probability they kill vidics.
This is due to a faulty PWM (DC-DC converter) and the fault does not appear without load! Without load, stable 3.3V, but it is worth connecting the load and we will receive pulses at the output with a swing of 12 volts, which will cause a breakdown in the video card chip.
Having changed places (on a working and faulty raiser), the defect went to a working riser, the faulty one worked accordingly.
The culprit PWM FR9888
To check your riser:
load the 3.3V line with a light bulb (you can use a car 12V from 10 to 55 watts) and measure the voltage at the same time, in no case should it rise above 3.3 volts, when overloaded, it should fall through but never get higher!
The video was uploaded to YouTube, the whole defect is demonstrated"
This is good info.