Power cable /GPU question


Roadrunr

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Win 11 Pro
Ok, I have a Corsair RM850x power supply and a Sapphire Pulse RX7800XT graphics card. The power supply came with cables that have two connections on the GPU end (I hate electrical stuff BTW). Am I good feeding both connectors on the GPU from a single cable? I currently have it set up with separate cables (because I think I read something about a 150W limit) but now I'm questioning whether that is per plug on the GPU side or whether that is on the PSU side.

Kind of asking because it looks dumb having that second connector hanging there (x2). I don't need the power for anything else so maybe my solution is to find some power cables without the second connector and just run those (but one cable and two connectors would be so much cleaner).

I know it's a dumb questions, I also know it works the way I currently have it set up but I figure it might help someone else who hasn't really built a computer in the last 20 years (like me) or ever.
 

My Computers

System One System Two

  • OS
    Win 11 Pro
    Computer type
    PC/Desktop
    CPU
    AMD Ryzen 7 9700X
    Motherboard
    MSI Mag B650 Tomahawk
    Memory
    G.Skill Trident Z5 Neo (2x32)
    Graphics Card(s)
    Sapphire Pulse RX 7800 XT
    Monitor(s) Displays
    MSI G274QPX (x2)
    Screen Resolution
    2560x1440
    Hard Drives
    (2) Samsung 990 Pro 1TB
    (1) Samsung 990 Evo Plus 2TB
    PSU
    Corsair RM850x
    Case
    NZXT H6 Flow
    Cooling
    Thermalright Phantom Spirit SE ARGB
    Keyboard
    Razer Huntsman v2
  • Operating System
    TrueNAS Scale
    Computer type
    PC/Desktop
    Manufacturer/Model
    Custom
    CPU
    AMD Ryzen 5 5600G
    Motherboard
    MSI B550M-VC Pro
    Memory
    Crucial 2x16gb
    Graphics card(s)
    Integrated
    Monitor(s) Displays
    None
    Hard Drives
    2x128gb m.2 (mirrored boot), 2x500gb Samsung EVO 870 (mirrored apps), 2x8tb WD spinning rust shucked from external Easystore enclosures (mirrored data)
    PSU
    Corsair 650W
    Case
    NZXT H7 Flow (needs replacing with something that has more drive bays)
    Cooling
    OEM boxed cooler
    Mouse
    none
    Keyboard
    none
I can't tell you what you should do, but I can tell you what I do.

I use two cables on my RTX 3070 Ti just to be on the safe side. I don't know the per cable rating of my PSU, so I think it's better to use two cables and not stress the PSU by drawing all of that Amperage out of a single dual plug cable. I think it's better to spread the load out between the PCIe circuits. It's not as neat and clean as the single cable approach, but I think my PSU will last longer as a result.

But that is just me. The electrical engineer in me is making me do this. It is not based on some hard, fast rule based on specifications.

Someone is going to come along and tell you that I am wrong, so you will have to make the decision what to do yourself. I am just stating my preference for connecting this stuff in my own PC. Your mileage may vary.
 

My Computer

System One

  • OS
    Win 11 Pro 23H2
    Computer type
    PC/Desktop
    Manufacturer/Model
    Self build
    CPU
    Intel i7 13700KF
    Motherboard
    Gigabyte Z790 UD AC
    Memory
    32 GB Team Group DDR5 - 6000 CL 30
    Graphics Card(s)
    ASUS TUF GAMING RTX 3070 Ti
    Sound Card
    On board Realtek
    Monitor(s) Displays
    2 x Samsung 32 inch curved - one 4K, one 1080p
    Screen Resolution
    4K, 1920 x 1080
    Hard Drives
    1 TB Samsung 980 Pro Nvme, 1 TB Samsung 970 EVO Nvme, 2 x Samsung 970 2TB SSD SATA
    PSU
    EVGA 1000Q
    Case
    Rosewill something or other
    Cooling
    Noctua NH-D15. A whole schwak of Noctua case fans. $$$
    Keyboard
    Logitech G815
    Mouse
    Logitech G502 Hero
    Internet Speed
    700 up, 600 down
    Browser
    Firefox
    Antivirus
    MalwareBytes
if you have the option to run 2 physical cables from the power supply to the GPU, I would do that. Even if it looks a bit dumb. I only use the little pigtail adapter if it's my only choice.
 

My Computers

System One System Two

  • OS
    Windows 11 Pro
    Computer type
    PC/Desktop
    Manufacturer/Model
    Beelink SEI8
    CPU
    Intel Core i5-8279u
    Motherboard
    AZW SEI
    Memory
    32GB DDR4 2666Mhz
    Graphics Card(s)
    Intel Iris Plus 655
    Sound Card
    Intel SST
    Monitor(s) Displays
    Asus ProArt PA278QV
    Screen Resolution
    2560x1440
    Hard Drives
    512GB NVMe
    PSU
    NA
    Case
    NA
    Cooling
    NA
    Keyboard
    NA
    Mouse
    NA
    Internet Speed
    500/50
    Browser
    Edge
    Antivirus
    Defender
    Other Info
    Mini PC used for testing Windows 11.
  • Operating System
    Windows 10 Pro
    Computer type
    PC/Desktop
    Manufacturer/Model
    Custom
    CPU
    Ryzen 9 5900x
    Motherboard
    Asus Rog Strix X570-E Gaming
    Memory
    64GB DDR4-3600
    Graphics card(s)
    EVGA GeForce 3080 FT3 Ultra
    Sound Card
    Onboard
    Monitor(s) Displays
    ASUS TUF Gaming VG27AQ. ASUS ProArt Display PA278QV 27” WQHD
    Screen Resolution
    2560x1440
    Hard Drives
    2TB WD SN850 PCI-E Gen 4 NVMe
    2TB Sandisk Ultra 2.5" SATA SSD
    PSU
    Seasonic Focus 850
    Case
    Fractal Meshify S2 in White
    Cooling
    Dark Rock Pro CPU cooler, 3 x 140mm case fans
    Mouse
    Logitech G9 Laser Mouse
    Keyboard
    Corsiar K65 RGB Lux
    Internet Speed
    500/50
    Browser
    Chrome
    Antivirus
    Defender.
I failed to quickly find a reference, but the general recommendation is to use two cables. (That begs the questions as to why cables with two connectors are supplied.)

If you are compulsive (like me), it's possible to buy single PCI-E cables, from Corsair or third parties. Amazon has a number of choices.
 

My Computers

System One System Two

  • OS
    Windows 11 26100.3025
    Computer type
    PC/Desktop
    Manufacturer/Model
    homebuilt
    CPU
    Amd Threadripper 7970X
    Motherboard
    Gigabyte TRX50 Aero D
    Memory
    128GB (4 X 32) G.Skill DDR5 6400 (RDIMM)
    Graphics Card(s)
    Gigabyte RTX 4090 OC
    Sound Card
    none (USB to speakers), Realtek
    Monitor(s) Displays
    Philips 27E1N8900 OLED
    Screen Resolution
    3840 X 2160 @ 60Hz
    Hard Drives
    Crucial T700 2TB M.2 NVME SSD
    WD 4TB Blue SATA SSD
    Seagate 18TB IronWolf Pro
    PSU
    BeQuiet! Straight Power 12 1500W
    Case
    Lian Li 011 Dynamic Evo XL
    Cooling
    SilverStone Technology XE360-TR5, with 3 Phanteks T30 fans
    Keyboard
    Logitech K120 (wired)
    Mouse
    Logitech M500s (wired)
    Internet Speed
    2000/300 Mbps (down/up)
  • Operating System
    windows 11 26100.3025
    Computer type
    PC/Desktop
    Manufacturer/Model
    homebuilt
    CPU
    Intel I9-13900K
    Motherboard
    Asus RoG Strix Z690-E
    Memory
    64GB G.Skill DDR5-6000
    Graphics card(s)
    Gigabyte RTX 3090 ti
    Sound Card
    built in Realtek
    Monitor(s) Displays
    Asus PA329C
    Screen Resolution
    3840 X 2160 @60Hz
    Hard Drives
    WDC SN850 1TB
    8TB Seagate Ironwolf
    4TB Seagate Ironwolf
    PSU
    eVGA SuperNOVA 1300 GT
    Case
    Lian Li 011 Dynamic Evo
    Cooling
    Corsair iCUE H150i ELITE CAPELLIX Liquid CPU Cooler
    Mouse
    Logitech M500s (wired)
    Keyboard
    Logitech K120 (wired)
Each power connector on the GPU should always have a separate power cable connected at the GPU end to its own pci-e connector at the PSU end. There should be no daisy chaining where there are 2 connectors at the GPU end going to one pci-e connector at the PSU end.

For example, I have a Sapphire 7900 XTX which has 3 connectors at the GPU end and three separate cable's connected at the PSU end.


Based on information on the website linked above an 8 pin pci-e connector can supply up to 150 watts. The Sapphire RX 7800 card in question can use up to 266 watts. So two connections to the PSU are required.

 

My Computers

System One System Two

  • OS
    Windows 11 Pro 24H2 26100.3025
    Computer type
    PC/Desktop
    Manufacturer/Model
    Homebuilt
    CPU
    Intel Core i9 13900K
    Motherboard
    Asus ProArt Z790 Creator WiFi - Bios 2703
    Memory
    Corsair Dominator Platinum 64gb 5600MT/s DDR5 Dual Channel
    Graphics Card(s)
    Sapphire NITRO+ AMD Radeon RX 7900 XTX Vapor-X 24GB
    Sound Card
    External DAC - Headphone Amplifier: Cambridge Audio DACMagic200M
    Monitor(s) Displays
    Panasonic MX950 Mini LED 55" TV 120hz
    Screen Resolution
    3840 x 2160 120hz
    Hard Drives
    Samsung 980 Pro 2TB (OS)
    Samsung 980 Pro 1TB (Files)
    Lexar NZ790 4TB
    LaCie d2 Professional 6TB external - USB 3.1
    Seagate One Touch 18TB external HD - USB 3.0
    PSU
    Corsair RM1200x Shift
    Case
    Corsair RGB Smart Case 5000x (white)
    Cooling
    Corsair iCue H150i Elite Capellix XT
    Keyboard
    Logitech K860
    Mouse
    Logitech MX Ergo Trackball
    Internet Speed
    Fibre 900/500 Mbps
    Browser
    Microsoft Edge Chromium
    Antivirus
    Bitdefender Total Security
    Other Info
    AMD Radeon Software & Drivers 24.12.1
    AOMEI Backupper Pro
    Dashlane password manager
    Logitech Brio 4K Webcam
    Orico 10-port powered USB 3.0 hub
  • Operating System
    Windows 11 Pro 24H2 26100.2894
    Computer type
    Laptop
    Manufacturer/Model
    Asus Vivobook X1605VA
    CPU
    Intel® Core™ i9-13900H
    Motherboard
    Asus X1605VA bios 309
    Memory
    32GB DDR4-3200 Dual channel
    Graphics card(s)
    *Intel Iris Xᵉ Graphics G7 (96EU) 32.0.101.6078
    Sound Card
    Realtek | Intel SST Bluetooth & USB
    Monitor(s) Displays
    16.0-inch, WUXGA 16:10 aspect ratio, IPS-level Panel
    Screen Resolution
    1920 x 1200 60hz
    Hard Drives
    512GB M.2 NVMe™ PCIe® 3.0 SSD
    Other Info
    720p Webcam
OK, thanks for the confirmation.

The pair of single cables is the route I was thinking to clean it up some. I need to pick up a SATA power cable with 4 connectors for my NAS too so I'll just grab that at the same time.
 

My Computers

System One System Two

  • OS
    Win 11 Pro
    Computer type
    PC/Desktop
    CPU
    AMD Ryzen 7 9700X
    Motherboard
    MSI Mag B650 Tomahawk
    Memory
    G.Skill Trident Z5 Neo (2x32)
    Graphics Card(s)
    Sapphire Pulse RX 7800 XT
    Monitor(s) Displays
    MSI G274QPX (x2)
    Screen Resolution
    2560x1440
    Hard Drives
    (2) Samsung 990 Pro 1TB
    (1) Samsung 990 Evo Plus 2TB
    PSU
    Corsair RM850x
    Case
    NZXT H6 Flow
    Cooling
    Thermalright Phantom Spirit SE ARGB
    Keyboard
    Razer Huntsman v2
  • Operating System
    TrueNAS Scale
    Computer type
    PC/Desktop
    Manufacturer/Model
    Custom
    CPU
    AMD Ryzen 5 5600G
    Motherboard
    MSI B550M-VC Pro
    Memory
    Crucial 2x16gb
    Graphics card(s)
    Integrated
    Monitor(s) Displays
    None
    Hard Drives
    2x128gb m.2 (mirrored boot), 2x500gb Samsung EVO 870 (mirrored apps), 2x8tb WD spinning rust shucked from external Easystore enclosures (mirrored data)
    PSU
    Corsair 650W
    Case
    NZXT H7 Flow (needs replacing with something that has more drive bays)
    Cooling
    OEM boxed cooler
    Mouse
    none
    Keyboard
    none

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