Confused about PSU's 20 vs 24 pin

Well let me first say what my specs are:

ECS 648fx socket 478 mobo 20 pin connector and the separate 4 pin
520w Aspire PSU 24 pin connector and a 4pin

My 12v rail is horrible at idle. It dips to 6v and as high as 12.8v.
I bought this PSU to upgrade so I could run my 7800GS on a stable 12v rail (above 11.8v all times).

Did I buy the wrong powersupply for my board? The PSU's connector has 4 pins hanging off one end of the 20pin connector on my motherboard..

Could that be why my 12v shows so low? The seperate 4pin connector on the PSU is plugged into the 4pin on the mobo.

I'm confused can someone enlighten me here.. On the description for the PSU on newegg it said "20+4 pin" so I thought okay, a 20 pin connector and a 4 pin connector. So it comes as a 24 pin and a 4 pin...

4 answers Last reply
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  1. The 20+4 pin setup is fine, the extra 4 are for mobo's that have the 24 pin socket.
    They just sit to one side, not connected for you mobo.

    Your PSU shouldn't be dropping that low, ever.
    Send it back for a replacement before it kills something in your computer.

    What is the make & spec's for your old PSU?
  2. You don't have the problem you stated. No system would run under such conditions, so the only other option is this: Your readings are wrong.

    That's a common problem. I suggest you go to Wal-Mart and get their "Popular Mechanics" digital multimeter for $9.88, then measure your 12v output with it. The nice thing besides being cheap is...this meter uses a 9v battery, which is cheaper to replace than the stack of watch batteries often used in smaller meters.
  3. If you end up replacing that psu please get something with a better reputation... Troll the threads on power supplies and look at the recommendations.
  4. I had to buy a new motherboard, the voltage regulators were bad. I checked with a multimeter and yes they were that low. My system started to reboot/crashed every 3 minutes when playing a game and my fps was horrible.

    With the new board I'm seeing 12.15 +12v, 3.35 for the 3.3v, and 5.10 for the 5v

    I have doubled my power supplies also running my case fans/HD fan/LEDS all off my 2nd power supply.

    I haven't crashed once in 36 hours my FPS in games is up over 100 at all times.

    I'm glad I checked the board before I RMA'd the PSU for no reason.. I'll never buy another ECS board again, now I see why ppl say they suck.. because they do. I'm considering a better brand PSU now (even though its working fine now) I can still send this back for a full refund, I'm looking at an OCZ or an Antec.

    Anyway thanks for the suggestions all is well now.
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