Antec CP-850 - No power from 8pin to 6pin PCI-E cables

Evening folks,

I have an odd issue with my PSU

I recently aqquired 2 Modular PCI-E cables to fit my Antec CP-850 - they are the ones that are 8pin from the PSU to 6pin for the Graphics cards.

I usually use supplimental Molex to PCI-E cables (1 6 pin to 6 pin from the PSU and 1 Molex to 6 Pin on each Card)

When I unplugged the molex cables from my Cards and plugged in the PCI-E cables I noticed my PC wouldnt turn on at all. Infact, the mobo wasnt even getting any power.

Something to note, we recently had an issue in the house with one of the lights causing a power trip (I figured it out cause my speakers were crackling, Monitor was flickering and PC was turning off at high loads). We fixed the trip and everything went back to normal.

However, I noticed that my speakers do an odd pop now and then, my monitor flickers at bootup (only bootup) and makes a funny noise on standby, and when I stress test my PC (Furmark Multi-GPU & IBT) it crashes after a few minutes (after my cards have heated up and are using full power)

Can any of you guys link this all up? Is my house electric still a little f**ked? or has it damaged my PSU?

I'm thinking that my Molex cables arent providing my cards enough power anymore, and when I switch to the PCI-E cables the wall socket crys and wont let my PC have anything. This is a guess though.

Help please xD


8 answers Last reply
More about antec power 8pin 6pin cables
  1. Are the modular cables the ones that came with that PSU? I've had an issue in the past where a PC wouldn't boot because I'd used another company's cable in the PSU I was using.
  2. Nah they were ones from a Thermaltake toughpower PSU

    If this is true, then that may be one issue solved.

    I just clocked my GPUs back to stock volts and stock clocks and ran furmark - seems to be fine.

    As soon as I crank more clocks into my GPU it shuts off

    I've tested it with 950mv - 1075mv @ stock clocks and its fine running Furmark

    As soon as I crank up the clocks though - bang - off it goes
  3. Never had a PSU issue before despite how long I've been working with PCs (My choice of PSUs seems to have been exemplary)

    Any help would be appreciated.
  4. I review products for a living and have seen modular PSU's that have different wiring for their modular cables. One company will wire their cable differently than another so that you have to use the companies cables and not another. Thermaltake for instance is different than

    I would check the cables to see if the wires are correct, I have actually been lucky and not fried anything because I used the wrong modular cable.

    Here's a Molex modular cable plug for two PSU's that have different wiring as an example. The grey and white striped cable is form a Thermaltake while the black is from an NZXT I think.

  5. Okay I get the modular cables issue.

    The real issue is the fact that this DIDNT cause the problem, this is AFTER the problem occured.

    So what about the rest of it? the shutdowns during furmark when gpu is OC'd, the Monitor flickering and the popping of speakers?

    PSU issue or Plug socket when taking what happened into account
  6. If you are still trying to use the modular cables, STOP.

    If the cables are giving your power to the wrong pins it may be frying something inside the PSU or your computer.

    If you unplugged an adapter that goes from a Molex to the PCI-e that connects to your graphics card and replaced this with a new cable and your computer will not turn on the cable has to be the problem. Take the cable out and try to connect things how they were.

    You are confusing the issue with what your posts are saying, please start from scratch to help clarify the issues you are having for better help.

    1. Currently does your computer turn on, and if it does are you using the old Molex adapter or the new modular cables? Or is the overclock the issue?

    2. If your system is running and you are saying that when you overclock the GPU it won't turn on then it may not be getting enough power when you overclock.

    3. If you are overclocking and after changing settings the computer does not boot up the overclock is at fault. It may not be getting enough power so a power supply with more wattage may be able to get you to a boot up during overclock. What is your system and what wattage PSU are you using?

    If your house electric is at fault you should have random shutdowns or odd things happening to all your computers and devices like current TV's. LCD and even CRT monitors will flicker and grow slightly brighter after being turned on as they warm up. Speakers popping occasionally is a usual sign of interference somewhere in your PC. Speaker wires that are close to power cables or wires that go from a sound card to your speakers that run along other higher powered wires can cause interference to the signal, creating a popping sound.

    You should never do two things at once when you are trying to solve a problem as it never tells you what the problem is. Go one step at a time and eliminate one thing at a time to get to the one that is causing your problem.
  7. deadjon said:
    Okay I get the modular cables issue.

    The real issue is the fact that this DIDNT cause the problem, this is AFTER the problem occured.

    So what about the rest of it? the shutdowns during furmark when gpu is OC'd, the Monitor flickering and the popping of speakers?

    PSU issue or Plug socket when taking what happened into account

    Have you tried another socket ?
    Is everything plugged into a surge protector ?
    System runs Furmark with no OC on the cards, download OCCT and run the psu test for a few minute's, then check the voltage graphs.
  8. I've checked another couple of sockets and still the same issue - I'm gonna try it downstairs too.

    I thought it WAS the surge protector that was broken at first (The issue occurred with the Surge protector installed) but apparently it wasn't.

    The issue with my monitor flickering is becoming more prominent now and the speaker popping is more frequent too.

    And to mention I used to run the Graphics cards @ 826/1652/1933 - 1037mv

    Ive tested the cards at the following settings with the following results.

    675/1350/1700 - 950mv - PASS
    675/1350/1700 - 1000mv - PASS
    675/1350/1700 - 1050mv - PASS

    750/1500/1800 - 1000mv - FAIL
    750/1500/1800 - 1035mv - FAIL
    750/1500/1800 - 1050mv - FAIL
    800/1600/1900 - 1037mv - FAIL

    Ive ran IBT (4.6Ghz) in parallel with Furmark (Non-OC'd) and watched the 3.3v 5v and 12v monitors (ASUS AI Suite II) and they were all PERFECT.

    3.32v idle and 3.3v load
    5.09v idle and 5.02v load
    12.17v idle and 12v load

    I'll run OCCT to check tonight though.
Ask a new question

Read More

Power Supplies Cable Power PCI Express Components