I recently bought the Radeon RX 480 G1 and noticed that the power connector had 8 pins instead of 6. My PSU is a little old, it's a Gigabyte GE-C420A-C2, 350W, and it has only a single 6 pin power cable. If i get an adapter, will I be able to run the card?

The card currently doesn't work. I've flashed my BIOS to the latest version, I've used DDU, used the included disk, but the fans on the card don't spin, the card however lights up, but that's with the mobo power. I've tried HDMI and DVI, but I always get no signal, and I have to use integrated graphics. The card doesn't show up in Device Manager. My mobo is a Gigabyte GA-H55-UD3H. Please tell me if I need to get a new PSU, or whatever is the problem causing my card to not work.


  • CPU: Core i5 661 quad core
  • GPU: went back to using the Nvidia GTS 250 (I want to use the Radeon RX 480 G1.)
  • disks: 1 HDD and 1 optical drive
  • PSU: Gigabyte GE-C420A-C2, 350W
  • mobo: Gigabyte GA-H55-UD3H

I bought a new PSU today, the Corsair VS550, but I'm still having the same issue! I'm currently on integrated graphics, but if u plug in the 6+2, and try to boot, the fans spin at max speed while the "fan stop" LED comes on. No display, but I still get a Post-error singe beep, signifying a successful boot. I'm starting to think the card's broken, but could it possibly be anything else?

The GPU isn't recognized by the computer in Device Manager, and I'm currently not using any display driver, only the Basic Display Driver.

I tested my graphics card in my friend's new computer. It worked like a dream. It appears my motherboard is way too old for a card like this. I'm going to get his motherboard, the one I tested the card on, because he is getting a new motherboard too. This should solve my problem.

  • If you look at the specs your PSU could just not be powerful enough to run that card. What other components do you have in your computer (CPU, number of disks)? This would suggest your card could use up to ~164 Watt without other components.
    – Seth
    Jan 17, 2017 at 9:29

2 Answers 2


You need to get a new PSU.

The long answer is that you're putting a video card with very high power requirements into a computer with what is really a low-powered power supply. 350W is the maximum output of the power supply. What it can produce reliably without strain is generally going to be 70% or less of that total number, and the new video card takes up nearly 50% all by itself.

The good news is that power supplies are relatively easy to replace. Get one with a peak output of 500W or more to make sure it still has a comfortable enough overhead given the newer, more powerful components in your rig.

  • Thanks, I'll go buy a new PSU, one with the appropriate connectors.
    – JustBlu
    Jan 18, 2017 at 1:23
  • New PSU, same problem.
    – JustBlu
    Mar 3, 2017 at 6:31

That power supply is actually rated at 420w peak, 350w continuous output and two 15A +12v rails (30A rating), it should be sufficient to run this rig (assuming you have mentioned everything, but I assumed two 120mm fans as well), and you can get an adapter online for a reasonable cost like this one. For that matter, most video cards will function fine with the 6-pin connector plugged in because the 2 missing pins are just ground connections, although this is very much NOT a recommended solution.

From your information, entered into a Power Supply calculator, this rig would require just under 300w power with an 18A draw on the +12v rail.

That said, upgrading to a modern 500 watt power supply would probably be the best choice given the age of unit to guarantee trouble free power the system.

  • Strange, this power supply does have 2 6+2's, and still nothing.
    – JustBlu
    Mar 2, 2017 at 22:37
  • 6+2 connectors are universal, they can be used for either 6 or 8 pin PCI-E power... I don't think your dealing with a power problem.
    – acejavelin
    Mar 2, 2017 at 23:31
  • Thats what I'm saying, there must be something else
    – JustBlu
    Mar 3, 2017 at 4:17

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