I have an MSI r9 390x with a g10 bracket and AIO I had this setup for about a year and decided that the vrms need better heat sinks so I bought theses:
https://www.arctic.ac/uk_en/h3-vrm-generic.html
after applying them I let them to properly attach overnight and when I plugged in the card for the first time the card booted fine and the temps were good and I had put it on stock clocks. I ran msi kombustor and after a minute the pc shut off and would not turn on and displayed error code b2. I don't know if my Gpu is dead or if it's my psu. I tried different pcie slots and removed the Ben heat sinks just in case they were shorting something out. I don't have another card to test he psu with any other suggestions for troubleshooting the problem. Pc details below.
motherboard: msi z97 gaming 5
cpu: I7 4790k
psu: EVGA 750w GQ
ram: 32gb hyper fury
gpu msi r9 390x