Jump to content
Search In
  • More options...
Find results that contain...
Find results in...

Connecting a GPU to a PSU

Recommended Posts

Posted · Original PosterOP

To avoid breaking my GPU, I thought I'd ask it first. So in the past I've always had my GPU (2 x 8pin) connected to 2 x 6 pins on my PSU (PSU came with 8 pin to 6 pin cables), which worked fine (though it would sometimes crash under very heavy load). I just noticed it also has 2 x 6+2 pin connections on the PSU. Can I connect those to the 2 x 8 pin GPU?

Link to post
Share on other sites

Yeah, if they're meant for the GPU, why not?

Quote me to see my reply!


CPU: Xeon X5650 OC'd to 4.4GHz @ 1.36V (courtesy of @XR6) Motherboard: Asus Sabertooth X58 RAM: 4x4GB G.Skill DDR3 1866MHz GPU: Asus RX 570 Strix Storage: WD Blue 1TB and a 128GB Kingston UV400 PSU: EVGA 600B Case: Fractal Design Define C Monitor: Dell G2410T and two Dell P2210 on a Steelcase Eyesite triple monitor stand Mouse: Logitech G403 Prodigy Wireless Keyboard: Northgate Omnikey Ultra Mousepad: Steelseries QcK XL with stitched edge Headset:  Sennheiser HD598SE


I like old-ass keyboards, Volvos, Thinkpads, and fountain pens.


Link to post
Share on other sites

Wait what exactly have you done in the past? Which motherboard has 2x6pin power out? 


Edit: ah, you edited. Ofc always fill ALL the pins on your GPU. 

Gaming HTPC:

R7 1700X@stock - Cryorig C7 - Asus ROG B350-i - Asus GTX 1080 Strix - 16gb G.Skill Ripjaws V 3333mhz - Silverstone SX500-LG - 500gb 960 EVO - Fractal Design Node 202 - Samsung 60KS7090 - Logitech G502 - Thrustmaster T500RS - Noblechairs Icon

Desktop PC:
i7 2600k @stock - H100i GTX - Asus P8Z77-i Deluxe - Asus GTX 1050Ti Strix - 16gb HyperX Fury 1866mhz - EVGA 750G2 - 250gb 840 EVO - 6TB WD My Book Duo (Reds) - Enthoo Evolv ITX - Dell U3415W - Benq XL2411T - Qpad MK-85 Brown - Logitech MX518 - Blue Yeti Platinum - Noblechairs Icon 

Boss-NAS [Build Log]:
R5 2400G - Noctua NH-D14 - Asus Prime X370-Pro - 16gb G.Skill Aegis 3000mhz - Seasonic Focus Platinum 550W - Fractal Design R5* - 
250gb 970 Evo - 2x500gb 860 Evo (Raid0) - 6x4TB WD Red (RaidZ2)


Audio Gear:

Hifiman HE-400i - Kennerton Magister - Beyerdynamic DT880 250Ohm - AKG K7XX - Fostex TH-X00 - O2 Amp/DAC Combo - 
Klipsch RP280F - Klipsch RP160M - Klipsch RP440C - Yamaha RX-V479


Reviews and Stuff:

GTX 780 DCU2 // 8600GTS // Hifiman HE-400i // Kennerton Magister
Folding all the Proteins! // Boincerino

Useful Links:
Do you need an AMP/DAC? // Recommended Audio Gear // PSU Tier List 

Link to post
Share on other sites

6 pin PCIe delivers 75 watts. 6+2 pin PCIe delivers double that.


Definitely use the 6+2 connectors. Never use an adapter for 6 to 8 pin.

I WILL find your ITX build thread, and I WILL recommend the SIlverstone Sugo SG13B


Primary PC:

i7 8086k (won) - EVGA Z370 Classified K - G.Kill Trident Z RGB - Force MP500 - Jedi Order Titan Xp - The venerated Hyper 212 Evo (with RGB Riing flair) - EVGA G2 650W - Black and green theme, Razer branwashed me.

Draws 400 watts under max load, for reference.


Linux Proliant ML150 G6:

Dual Xeon X5560 - 24GB ECC DDR3 - GTX 750 TI - old Seagate 1.5TB HDD - Dark moded Ubuntu (and Win7, cuz why not)


EVGA G3 threadSeasonic Focus threadUserbenchmark (Et al.) is trash explained, PSU misconceptions, protections explainedgroup reg is bad

Link to post
Share on other sites
Posted · Original PosterOP
4 minutes ago, FloRolf said:

Wait what have exactly have you done in the past? Which motherboard has 2x6pin power out? 

my PSU has a 2x 6pin power out (and 2x 8 pin)

Link to post
Share on other sites
13 minutes ago, Fasauceome said:

6 pin PCIe delivers 75 watts. 6+2 pin PCIe delivers double that.


Definitely use the 6+2 connectors. Never use an adapter for 6 to 8 pin.

NO.  The cables don't know anything, they'll transfer as much energy as the video card demands.


If you have issues that you think are caused by the power quality, it's more likely that the power supply can not provide that amount of energy, and changing the cables won't make a difference.


The PCI-E Standard says that a video card should not take more than 75w from a 6pin connector, or 150w from a 8 pin connector - the wires and the physical connectors are capable of much more than that, the 6pin connector for example is good for up to around 3 pairs of wires x 9A per pair x 12v = 324 watts.

The 9A is a physical limitation of the metal pins inside the housing (the plastic of the connectors) - more is possible but you risk overheating the connectors or having loose connections inside the connectors. There are also connectors rated for more (ex 12-13A per contact), especially for EPS (cpu 8 pin), which use thicker filled pins capable of carrying safely more current.


So because a video card can not be called pci-e video card and can't put on the box any mention of pci-e if they exceed this amount of power drawn from the power supply, that's what happens... the video card bios will refuse to work with a 6 pin cable inside instead of 8 pin, even though it could. 

The two extra pins in the 8pin connector are just used to give the video card the "permission" to take more than 75w, as an analogy it's like a read-only hole on a cassette tape or floppy disk which prevents you from recording data on the medium ... the two wires are just that, a flag telling the video card it's allow to suck more than 75w of energy from the power supply.



Definitely use the 6+2 connectors. Never use an adapter for 6 to 8 pin.

An adapter will simply add those two wires which tell the video card "it's allow to take more than 75w". There's additional losses at the connection point (between adapter cable and the cable from power supply), but that's practically nothing, less than 1 watt of energy converted to heat and a few mV lost due to the resistance in the connector contacts.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now