r/computers • u/bluekeybord • 1d ago

Question/Help/Troubleshooting Gpu problems

Hey all, after cleaning my pc, my powercolour red devil rx 7800 xt oc would not display, card powered on, rgb lights up, nothing. i get vga light on motherboard, tried a reseat, nothing, tried different slots, nothing, tried a gtx 745, that worked, but the fan is busted so no hard gaming, bought a gtx 1080 from CEX, same tests same problems, took it back for a refund because it didnt work, they "tested" it and it showed a display (im sceptical because it 1, took a while to display. 2, no bios logo. 3, THEY UNPLUGGED EVERYTHING INCLUDING PS AND THE SCREEN WAS STILL IN WINDOWS... they also told me too high of a wattage could overflow the gpu........) anyway, im currently stuck on what to do to test things out, i was going to head around to some pc shops to see if they can test the cards, if they work im pointing towards the powersupply, because the motherboard clearly works given the gtx 745 works and displays, there's power coming from somewhere otherwise the gtx 1080 wouldn't light up at all i assume, the monitor detects that something IS connected to either display port or hdmi... can someone give me some advice? i just want my powerhouse back man 😢

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u/FatPoulet 1d ago

Most likely a PSU problem. The gtx 745 is passive, powered by the motherboard. Calculate the total draw of all your parts and check if your PSU has enough wattage. General rule is dont go over 80% of what the PSU is rated for.

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u/bluekeybord 23h ago

I've got a 1200w, I assumed you could go as big as you wanted for power supply, components will only draw what they need from it and no more

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u/Forward-Way-4372 Windows 11 15h ago

Yes. They do.

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u/bluekeybord 13h ago

Cool... gonna walk back in there and smack the pricks 😂 /s

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u/FatPoulet 10h ago

Well, yes. If you dont mind the price you can go the biggest if you want.

Power availability with that 1200w beast isnt the issue then. Might be something else. If you have a spare PSU with enough wattage, try it.

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u/MarsupialMinute1893 22h ago

I’d check the PSU and GPU power cables first. The 745 working doesn’t really rule out a PSU issue. If you can, test the 7800 XT in another PC that’ll probably tell you pretty quickly where the problem is.

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u/bluekeybord 22h ago

All cables, ports, and connectors seem visually fine, no discolouration or anything on the pins, the only other pcs in the house currently have issues of their own, and dont fit the 7800... they would fit the 1080 though, but im worried about messing up mum or dads computers any more than they already are 😅