Do I need to connect power supply to graphics card?

Solution


In addition to the words of wisdom offered I thought I could offer a bit of clarity about the why behind the what which is the PSU.

You said

even though inserting it in the motherboard turns the card on and fans work

Why does the card work but not really?

The PCIe slot that accepts the GFX card has 75W of power to offer its resident. Should its resident need more food it...
Yes, you need to connect an 8-pin PCIE supplemental power connector to your GPU in order for it to work.

If your PSU doesn't have this, then it is a clear indication that your PSU cannot power your upgraded system. I highly recommend you get a new good-quality PSU. What is your CPU/MB/RAM, and what is your actual RX 480 model (am assuming its MSI, but just to be sure)?
 


I can buy another power supply I just want to know which power supply will power everything else and power up the graphics card as well. Sorry I'm new at this stuff.
My cpu: Gigabyte GA-78LMT-S2PT
And the GPU is a Msi
 


I'm looking at going to pick this up today:
Corsair - CX Series Modular CX750M 750W ATX Power Supply - Black
I just gotta learn how to plug everything in
 


You don't need 750W PSU, that's definitely an overkill for your system. The CX750M costs ~$80. If you're willing to spend that much for a PSU specifically for your rig, then get this instead:

EVGA SuperNOVA G3 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($84.99 @ NCIX US)

Better quality, better warranty, higher durability, and ample wattage.

If you want to save some bucks, then my previous suggestions above will also do.
 


In addition to the words of wisdom offered I thought I could offer a bit of clarity about the why behind the what which is the PSU.

You said

even though inserting it in the motherboard turns the card on and fans work

Why does the card work but not really?

The PCIe slot that accepts the GFX card has 75W of power to offer its resident. Should its resident need more food it has to look to PCIe supplementary power cables. When we look to its appetite http://www.guru3d.com/articles-pages/amd-radeon-r9-rx-480-8gb-review,5.html it does need more than 75W which means cables are necessary and required. Connect a 6 pin PCI cable and you will only be offering it up to 150W total which is less than what it needs. Step up the cable to an 8 pin and you are now offering the card an additional 150W of power which means the card will have access to up to 225W, which well exceeds its 166W need, which means you need an 8 pin supplementary power cable. WIthout that 8 pin cable you will have a card which has enough power for fans and light(s) but for it to fully perform its duties it needs help.

In short

PCIe slot - 75W
6 pin PCIe supplementary power cable 75W
8 pin PCIe supplementary power cable 150W

The aforementioned G550W will power your card with ease. I don'ty think OC'ing is on the table at the moment but that card offers you enough headroom to do just that. The next question is how long will it be before you upgrade your GFX card and what will it be? Do you want to buy another PSU when that upgrade comes or do you want to invest in some longevity? Should you want to invest in some longevity I recommend https://www.newegg.com/Product/Product.aspx?Item=N82E16817438054 . In addition to its Gold certification for its electrical efficiency it is also fully modular. That means you only connect the cables you need which reduces the amount of cables under the motherboard(thanks to Capt. Obvious 😀) which means a cleaner/neater build. With a 7 year warranty behind the PSU it should quite easily last through a couple more builds.
 
Solution