Computer turning on and off repeatedly with new PSU

Recently got a new gpu (xfx hd7950) and psu (corsair hx650). When I try to turn my computer on with the new parts installed it turns on for a few seconds then off again, sometimes having the fans spin sometimes not. I took the gpu out and put the old one back and the problem continued. when I put both my old psu and gpu in it works fine. Im assuming its a compatibility issue with my motherboard (pegatron model 2A86). The computer is a couple years old now and I am wondering if I should even bother trying to fix this or go straight for a new pc.

intel I7 950@ 3.07
radeon hd6450
pegatron 2A86
4 sticks of 4gb ram totaling 16gb (unsure of who made it because it has now markings on it)
9 answers Last reply
More about computer turning repeatedly psu
  1. Check the power supply output amount for the new PSU, might not have enough juice. Most likely reason is that the new PSU is broken.
  2. For a system using a single AMD reference design Radeon HD 7950 graphics card AMD specifies a minimum of a 500 Watt or greater system power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 30 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

    Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Sufficient Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the most critical factor.

    The Corsair HX Series HX650 (SKU# 75-001217 / CP-9020030) Power Supply, with its maximum combined +12 Volt continuous current rating of 54 Amps and with two (6+2)-pin PCI Express supplementary power connectors, is way more than sufficient to power your system configuration with a single Radeon HD 7950 graphics card.

    It's not a lack of power supply capacity at all but your problem can still be caused by a defective power supply unit.
  3. Did you figure anything out?
  4. Sorry for the late reply, I'v been having internet troubles. I sent the PSU back as DOA and the replacement causes the same problem. I assume it is more a problem with my motherboard than the PSUs because what are the chances the replacment being DOA also?
  5. will the new PSU and old video card work? Also check the BIOS settings for video interface. you may have something set to a static setting, when you want auto, or the setting needs to be adjusted. When installing new hardware, it's often a good idea to load standard defaults for BIOS to make sure the hardware is working, then you can try optimized defaults, or custom settings.
  6. The new PSU wont work with either video cards my bios is set to default.
  7. Was the 4-pin ATX 12V Power connector on the motherboard for the CPU connected to the power supply unit?

    If the motherboard doesn't receive a PWR_OK or Power good signal from the power supply it won't power up or stay powered on.
  8. It was. Just as my old psu is now. But the new PSU has 2 4pin cpu connectors. Would that make a difference because I only have 1 4pin slot.
  9. it shouldn't. In fact, some newer MoBo's use both 4-Pin connectors as an 8-pin connector, but if yours only uses 4-Pin, you're fine. The PSU does pass a basic diagnostic? IE: PSU tester shows it is working, or jumper green line to any black line and the PSU will power on fine.
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