Dust removal

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So windows works now? I wonder why neither display worked. Shouldn't need to reset CMOS just to change GPU. I know I didn't.

Do you have a return period? I would perhaps hold onto 1000 for a while if you can, just in case you need it

I think the displays weren't working because I was using the one psu cable for the graphics card. I read that you can only get 250W (or less) per cable and the card needs 300W.

Not entirely sure why I needed to reset cmos though.

I think I have a 2 week return period. Might be a good idea to hold onto the new psu for a bit. Thanks.
@Alm in theory 750W should be more than enough for your CPU and a 7900XT for a basic system with a couple of hard drives and a few lights. Should be 150W to spare even with 400W spikes considered with all components under a stress test.

If the PSU is getting on in age and maybe close to or out of warranty though if it were me I'd replace it anyway. And as Colif said keep hold of it until youre sure it works fine playing stressful games a few days just in case whatever happens.

Shouldn't need to reset CMOS just to change GPU.

Shouldnt need to afaik either, but electronics are weird. Few months ago I though my card was bricked. Out of nowhere wouldnt boot to Windows or BIOS red light for VGA on motherboard. Re-seated RAM, GPU reseat and repasted, cables changed and nothing helped. Took out and replaced CMOS battery on a hunch and everything booted up no problem.
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resetting it just means some bios setting was wrong. replacing it means the battery was probably dead. That happens over time. Although i have yet to have it happen in any PC I own, I have seen it fix things before.

I think the displays weren't working because I was using the one psu cable for the graphics card. I read that you can only get 250W (or less) per cable and the card needs 300W.

75 watts for pcie slot
75 watts for a 6 pin
150 watts for an 8 pin

Its why I asked about cables, I am using 2 myself but the 1000 has a few to spare. I should add more ssd as I have 10 sata power connectors now.
7900xt needs 315 so it makes sense it needs 2 pcie connectors.

As for if you need 2 cables, there is an answer here -

The power must still be carried from the PSU to the GPU, and it's here where the ATX standards are the most restrictive, and for good reason: the PSU supplies power and the GPU will take as much power as it needs, but neither does so with much regard to what's between them. If the PSU can't supply enough power, it will shut itself off*. If the GPU can't get enough power, it will shut itself off. If the wires get too much power, they will melt - or worse, catch fire. Accordingly, the ATX standards set the safety margins (6 pins for 75W, 8 pins for 150W) far below the point where this will occur. But to further confound the issue, both 6 pin and 8 pin connectors have the same number of current-carrying wires in them: 3. While there's some debate as to the purposes of the extra pins, the 3 hot wires within both cables indicate that both can carry the same amount of current. This is why a 6+2 pin is effectively equivalent to an 8 pin cable - there's no increased electrical risk. At the end of the day, the only real difference between the 6 and 8 pin cables in general is to inform whatever is using them of how much current is intended to be provided. It does nothing to stop anything from drawing more.


in theory teh cable should be able to supply all 300w but clearly it wasn't working.

it worked fine for my 2060super with 1 8 pin & 1 6 pin but its power draw is only 175watts so unlikely much extra came over the 6 pin
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I wonder what BIOS setting would affect one GPU and not another, weird.

I finally got it working!

Turns out clearing the cmos resets the bios and I needed to re-disable CSM to get Windows 11 to work.

Thanks for all the help everyone!

Do you think I should keep the rm1000x or should my rm750 do the job?

Turns out @Alm already answered that question and I have the memory of a goldfish :D
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I wonder what BIOS setting would affect one GPU and not another, weird.
Probably never know, as his solution wiped the settings so it would just be a guess. More so without knowing what motherboard he has,

Just glad to see a 7900xt work. I answer posts on Tom's and you tend to forget that people who don't have any problems tend not to come onto forums to report that fact. So the only ones I seen have had problems but I know 3 people who have them and had no problems.

Guess I should upgrade my drivers but they have released 3 so far this month. Nvidia you lucky to get one a month.
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its kind of pointless knowing what cause was now its fixed.

what CPU do you have? Its possible that when you removed your GPU the bios set the IGPU as the default and that might explain why you didn't get a picture on either. Resetting bios may have made BIOS aware of the GPU and disabled the igpu connections.

motherboard has HDMI connection that can be powered by CPU provided CPU has IGPU cores.

Thats just a guess. I don't know if its actually what happened. If you ran DDU and uninstalled Nvidia drivers and turned PC off and installed the AMD card, it shouldn't have had any chance to swap BIOS settings

I don't think guess is right after looking at bios settings. The default settings is
Initial Display Output
Specifies the first initiation of the monitor display from the installed PCI Express graphics card or the onboard graphics.
PCIe 1 Slot Sets the graphics card on the PCIEX16 slot as the first display. (Default)
which is where GPU is.

page 32 - https://download.gigabyte.com/FileL...d_v2_e.pdf?v=021eaf0e44271a7ec1a1544dcb4a5ee3

might have just been lack of power causing strange things.
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