PLEASE HELP RX 480 CRASHING

[djlukeyb89]

Dear Linus Tech Tips PLEASE HELP ME
I have issues with my rig its a new build every thing works fine untill i try gaming then after a few minutes i get a grey screen a buzzing noise and i have to reboot my computer. I have tryed every form of help out there and evry guide i can find the only things thats make any difference is droping the gpu voltage in gpu tweak by 16% i can game for a hour of so then the same thing. I have tryed a new psu,undoing all overclocks,fresh install of windows 10, i rma'ed my rx480 after 2 weeks i got it back saying theres nothing wrong with it. i have run furmark for a few hours with out any crashing.Please can you help me.
I have uploaded a video to youtube of hwmoniter and gpu tweak my temps all look ok im not to sure what to do next.
https://youtu.be/82oBb_Rfytw
my rig is
amd 6300
gigabyte ga-990x-gaming
hyperx fury 12gb ddr3 ram
asus rx480 dual 8gb oc edition
interator mod xt 750w psu
cpu water cooler
4 120mm fans
1tb wd blue hdd

[AvocadosGuac]

Its a GPU issue. RMA again and say you want a new one.

[RandoNandoz]

rma.

[djlukeyb89]

Hi I rma the card after they tested it they told me there was no fault found and are sending the card back to me they can't offer a refund of replacement as they haven't found any faults with it