New case, new GPU - Rest same - No power?

Dear Tommies,

Today I replaced my 6600GT with a HD5850, quite an upgrade.
I also moved all my components to a way bigger case.

I'm very sure everything is connected properly but the system just won't do anything.

As for the minimum to start a system:
PSU cable in a power socket: Check
PSU 24-pins ATX on the mobo: Check
2x4-pin ATX on the CPU: Double-molex to 6-pin (this should suffice since the board should also start with 1 4-pin. 2x 4-pin is only for >130w CPUs)

My setup:
600W Modular Zalman
GA-EP45-UD3P
E8500 C0 (Intel Stock)
4x1GB Team Xtreem PC2-6400 CL4
MSI ATi Radeon HD5850 OC

Again, the only new components are the GPU and case. Even without the GPU inserted there's no sign of power at all. The PSU should be able to keep up with the card anyway.

The power switch on the PSU is on too.


I'm really feeling dumb at the moment since I'm fine with computers but have been working on this b!tch all day.

Any input is more than welcome!
10 answers Last reply
More about case rest power
  1. Try using the 4 pin CPU power.
  2. My PSU has a 2x4-pin connector ready for the CPU power.. The only problem is that the Full-size tower is too full-size for the cable its reach. In short: It can't get there.

    The only way to get any cable to the 2x4-pin with this PSU is to use an adapter, which I did on 2xmolex -> 6-pin.

    In my previous case I did use the 2x4-pin so it is an option, but it should work any way, right?
  3. No, the 6 pin is a PCIe connector for video cards.

    Unmount the PSU and plug in the 4/8 pin CPU power, just to see if that's the problem.
  4. Am I to understand you have a 6pin pcie connector plugged into the 8pin motherboard power connector?

    Did you look at the wiring diagram and make sure that isnt putting a hot wire into a ground slot or worse???. You could do damage if the pinouts are not correct.

    Just plug the 4 pin into the 8pin slot like aford said. You should do some searching on this, as you have to plug it into the correct side. There was a thread on that exact issue about 3 months ago on this site somewhere.
  5. Yeah it supposedly is, on the other hand the pins match perfectly fine.

    I'll give that a shot just to be sure. Reaction's probably going to follow tomorrow.

    Anyway, I would need 2x4-pin adaptar or so if this would be the problem?
  6. Your graphics card requires two 6-pin PCI-E power connectors. You only mention one. Do you have both PCI-E power connectors connected?
  7. Yeah the GPU is fine.

    The system would boot with the GPU not having enough power anyway, especially in idle mode.

    I'll post back in 20-30 with the results of the PSU.
  8. No, the system will NOT boot if the GPU is not properly powered? What makes you think otherwise?
  9. Well it is the 2x4-pin alright.

    Sucks for me I'll need to get an adapter somewhere, some how.

    Thanks for the heads-up.


    About the GPU. I remember PCs showing signs of power without a GPU installed. Mine did not gave any sign of having power - that was the problem.

    All fine now, thanks.
  10. At least it's a cheap fix.
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