Question When installing Geforce RTX 4080 TI into PC case, Monitor doesn't get signal and doesn't display anything.

[Mediocreattech]

System information first:

OS: Microsoft Windows 11 Home

CPU: 11th Gen Intel(R) Core(TM) i7-11700F @ 2.50GHz, 2496 Mhz, 8 Core(s), 16 Logical Processor(s)

GPU: Currently 3060 ti while I figure out 4080 ti problem

Memory: 48GB

Monitor: Samsung monitor, that's all I can really remember (I got the build around 3 years ago so I can't remember it nor find it in system settings)

While installing the 4080 ti, I had to remove a fan to get it inside the case (I don't know if that's important in this scenario but I'm adding it in anyways). Another issue I came across while installing the 4080 ti was that where your supposed to plug in 3 power cables from your power supply into the GPU I only had 2 (again, this might be important to add just incase). After everything was plugged back in after installing the 4080 ti, I turned my computer on. Everything seemed to be functioning fine but the monitor didn't display anything, I tried changing the monitors settings, I tried unplugging the HDMI cable and re-plugging it back in, but nothing seemed to work. After I bit I tried installing my old GPU (3060 ti) and everything worked fine again. Now I'm not a tech wizard or anything, so if I could get some information on what could be going on or how I can possibly fix this it would be much appreciated.

 

[KingLoki]

Is you hdmi cable old? What version is it? Have you tried another cable?

 

[boju]

4080 ti doesn't exist, do you mean super?

In any case, need to connect the three pcie 8pin connectors, just two won't work. What's your power supply?

 

[Mediocreattech]

Is you hdmi cable old? What version is it? Have you tried another cable?

The cord should be around 2-3 years old, don't know the exact version however I don't think the problem should be tied to the cable, as with other GPU's (like my 3060 ti) it works great. I could still be wrong however.

 

[Mediocreattech]

4080 ti doesn't exist, do you mean super?

In any case, need to connect the three pcie 8pin connectors, just two won't work. What's your power supply?

Yeah I mean super, sorry for the confusion, also I'll check the power supply in a second.

 

[toooooot]

I recall when I last launched a PC without GPU power cables connected, it was just a black screen as well.
From your description, you do not have all power cables connected to the new GPU, correct?
I recall that their new 12vhpw cable connects to 3 typical PCIe cables (for 4080) which are connected to the PSU.
Did you connect 3 PCIe cables to the new 12hpvr?

 

[Mediocreattech]

4080 ti doesn't exist, do you mean super?

In any case, need to connect the three pcie 8pin connectors, just two won't work. What's your power supply?

My power supply is a EVGA 600 MW

 

[Mediocreattech]

I recall when I last launched a PC without GPU power cables connected, it was just a black screen as well.
From your description, you do not have all power cables connected to the new GPU, correct?
I recall that their new 12vhpw cable connects to 3 typical PCIe cables (for 4080) which are connected to the PSU.
Did you connect 3 PCIe cables to the new 12hpvr?

From my digging from within my pc case, I could only find 2 PCIe cables and thought I would have to work with that, from all these new comments however I think my former opinion may have been wrong.

 

[Angel Fernandez]

If you have a modular power supply add a third PCIe cable, then try. If your power supply is not modular you may not get one

 

[Mediocreattech]

If you have a modular power supply add a third PCIe cable, then try. If your power supply is not modular you may not get one

I think I figured out the main issue, my power supply isn't enough for the 4080 super and everything else, I'll have to buy a new one and another PCIe cable.

 

[boju]

I think I figured out the main issue, my power supply isn't enough for the 4080 super and everything else, I'll have to buy a new one and another PCIe cable.

Buying an adequate psu will have 4 or more pcie cables so don't plan on buying another seperate cable. Also atx 3.1 psus are available so you can do away with adapters and use straight out 16pin 12vhpwr cable.

Fyi, can't mix / use different cables (cpu 12v, atx, pcie, sata) from other fully or semi modular psus or off the shelf cables even if they look and fit the same. Psu industry don't follow pinout standards and fry components if use the wrong cable not meant for your power supply. Don't make that mistake and strictly only use cables the psu comes with.

Corsair Rm850x atx 3.1

https://www.corsair.com/us/en/p/psu...bO_61N_thDfRsMU60HNN3yTVYR2PCnJRBTa9JImhapmhU

Others here

Best PSU Picks 2025 - Hardware Busters

Hardware Busters - Best PSU Picks 2025 - Best Picks

hwbusters.com

For 4080/4080s, 850w minimum id recommend.

 

[iTRiP]

It's probably the issue, that the GPU isn't connected to the PSU properly using all required connectors.
(and by the sound of it the PSU probably isn't adequate to power this kind of GPU, what did he say 600Watt, yeah probably not a good idea for running a 4080)

Funny this even if that where too be sorted, sounds like something similar I heard of that some GPU's have what some call hot plug on first install with the monitor, well anyway might be of use, but I don't know if that's true or not. (something along the lines of that you had to power up the pc first then only plug in the monitor or else it won't display)

 

[Gaidax]

If you already are shopping for a new PSU, make sure to go for 1000w+, modular and ATX 3.0 or higher support.

Yes, technically 850w should be enough, but it's better to err on the side of caution there and get a bit more room there, after all - who knows maybe you'll decide to upgrade your system further down the road.