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Windows 7: 4pin of a 20+4 pin mobo power was n0t plugged in. What happens?

24 Jul 2012   #1

Windows 7 Home x64 & Windows XP Pro x86
4pin of a 20+4 pin mobo power was n0t plugged in. What happens?

Hello, i have some simple questions. My system randomly turns off. no blue screen. No crash dump. no windows shutdown screen. This isnt really about the shutdowns.

1 - What happens when the 4pin connector of a 20+4 pin mobo power plug is disconnected

2 - Does the 4pin connector give more stability to a pcie2.0 x16 Graphics Card?

3 - What damage could have been done?

Ive swapped the graphics card out with a Power Color HD4850. The shutoffs happened with both.

I have four ram chips. i took out 2 and it still shutoff. Im now trying the other two.

Thank you for your time.

My System SpecsSystem Spec
24 Jul 2012   #2
Microsoft MVP

Windows 7 Ultimate SP1 X64 (Windows 10, 8.1, Linux Mint, Windows XP and others in VM)

To answer your questions, I really don't know. But, I would suspect the +4 pin will supply more power to the motherboard. The 20 pin will supply enough power for it to run but not quite as much as it should have. I would not worry too much about any damage to the board. The GPU gets most of it's power from the pcie conntections, but the extra 4 pins may help. As far as the memory, I would suggest running memtest86 to test the memory. The link is to a tutorial on how to run it. You are looking for bad ram sticks or defective dimm slots.
My System SpecsSystem Spec
25 Jul 2012   #3

Windows 7 pro 64bit. (SP1)

on 20+4 atx plug the 4 additional pins give more power that pc demands nowadays, especialy with high end GPU.
if its not connected motherboard tries to draw all the power from 20 pins.. that may be okay but in extreme cases where lots of power are used it may melt wire or connector, because current is too high. or it may just add stability problems when system dont get enough power.
My System SpecsSystem Spec
25 Jul 2012   #4

Windows 7 Ultimate x64 SP1

I'm surprised it booted without giving you a warning or a message to click through.
My System SpecsSystem Spec

 4pin of a 20+4 pin mobo power was n0t plugged in. What happens?

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