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8-pin pwer connection, all I have is 4 pin?

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January 18, 2009 1:53:40 AM

12V Molex to 8pin P8 Adapter is what I am having to buy online because I called around and no local stores even knew what I was talking about.

Basically my case's PSU didn't come with the 8-pin motherboard power connection.

When you look at the 12V Molex to 8pin P8 Adapter it has [2] molex female connecter going into the 8pin connector. Am I Suppose to connect 12 volts of power to EACH molex or just one female molex?

Here is a link to the product I am talking about. http://www.newegg.com/Product/Prod [...] 6812887002

It's Item#:N82E16812887002 on www.newegg.com

I have also tried to power my system with the video card removed and it still would not make the HSF's fans to work properly.

Is this purchase for this 8-pin connecter going to solve this problem?
Also, does the 8-pin only require 12 volts or does it need 2x12=24 volts to power the motherboard?

Here is the motherboard I bought
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
This is the Case which has a 500 watt PSU inside it [has not got a 8-pin connecter as I mentioned that I need]
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I eagerly look forward to your answers.
a b ) Power supply
a c 229 V Motherboard
January 18, 2009 2:39:45 AM

That PSU has a 4-pin CPU connector and that should be good enough unless you bought an extreme CPU that draws 130W. Refer to page 23 of the motherbaord manual for more info.

You can see the 4-pin CPU connector on the last picture at the bottom of this page: http://www.chiefvalue.com/product-_-showimages.cv_-_ima...
January 18, 2009 3:28:50 AM

I tried connecting just the 4-pin connector into that 8-pin box on the edge of the MB but it wouldn't power the heat sink's fan, the other fans all spun.

So when I get this 8 pin molex connector via ups I'll still just be sending 12 volts, nothing special on the voltages between a 4 pin versus a 8 pin is there?

EDIT: My CPU is a quad core 2 duo [ q9400] not an extreme CPU.
Related resources
a b ) Power supply
a c 229 V Motherboard
January 18, 2009 1:03:26 PM

I know that you connected the 20+4 pin power cable, otherwise nothing would happen when you try to power up.

Was there a black protective cover hiding 4 pins of the CPU power connector on your motherboard (mine didn't have one)? If not, did you connect the 4-pin CPU cable to the 4 pins closest to the CPU? As far as I'm concerned, you shouldn't be able to connect it to the the 4 pins closest to the back of the system (I definitely can't on mine, but my PSU has both the 4-pin and 8-pin CPU power cables).

If everything is connected properly, using an 8 pin molex connector won't help (unless the 4-pin cable has no power, which would be the sign of a defective PSU). In other words, if it doesn't work now, wating for that cable is sort of useless.

What are the specs on that PSU?
January 18, 2009 6:10:53 PM

I surely do hope those 2 4-8 pin adapters solve the issue because I have waited [so far] 3 days and spent with tax and shipping nearly $30 for those adapters.

As I said, we tried to just use the 4 pin we had and put in the half of the 8-pin on the board that would accept it. It didn't make the cpu fan spin although the other case fans spun.

Are you saying that if the 4 pin connected to the 8-pin should spin the cpu fan at least? And if it doesn't do this with just the 4-pin that waiting to use the adapter is useless since this would mean the 4-pin has no power coming out of it to begin with?

Is there a safe but effective way to test with a multimeter the volts coming out of that 4 pin from the psu?

I also have no idea who made the PSU, all I know is that it is suppose to be 500 watts powered.

anything else?
a b ) Power supply
a c 229 V Motherboard
January 18, 2009 7:19:19 PM

Quote:
Are you saying that if the 4 pin connected to the 8-pin should spin the cpu fan at least? And if it doesn't do this with just the 4-pin that waiting to use the adapter is useless since this would mean the 4-pin has no power coming out of it to begin with?
Unfortunately your solution isn't very likely going to work.

When you power up, the CPU fan doesn't spin right away; it starts spinning several seconds later. To test the PSU with a multimeter, put the positive lead on a yellow wire connector and the negative lead either on a black wire connector or on the chassis. If the CPU connector doesn't provide 12 volts, then the PSU is defective, not powerful enough or something is shorted out. Can you try a different PSU? There is an image of the PSU at the link that I provided before. According to the picture, that PSU has a single 12V rail rated at 22 amps. That might be good enough, but what other components do you have in that system (as detailed as possible would be very helpful)?

Did you test the motherboard outside of the case with just one memory module, the CPU and the video card if it isn't one that draws a lot of current (nothing else should be connected, not even a mouse or keyboard)?
January 18, 2009 8:53:19 PM

Are you saying that it's normal for the cpu fan to NOT spin immediately and that it spins later on in a few seconds?

My system is
this PSU is being shipped to me now, not part of my system YET
OCZ GameXStream OCZ700GXSSLI 700W ATX12V SLI CrossFire Ready Power Supply
Item #: N82E16817341002

This is the case RAIDMAX SMILODON ATX-612WBP Black Mid Tower Foldout MB Case 500W
Item #: N82E16811156062

for the cpu Arctic Silver 5 Thermal Compound
Item #: N82E16835100007

dvd burner SAMSUNG 20X DVD Burner with LightScribe Black SATA
Item #: N82E16827151179

unwanted gift Nvidia Gift
Item #: N82E16800999088

for the cpu Arctic Silver ACN-60ML (2-PC-SET) Thermal material Remover & Surface Purifier
Item #: N82E16835100010

OS Microsoft Windows Vista Home Premium SP1 64-bit for System Builders
Item #: N82E16832116488

Video Card EVGA 512-P3-N871-AR GeForce 9800 GTX(G92) 512MB SLI Video Card
Item #: N82E16814130339

Motherboard GIGABYTE GA-EP45-UD3P LGA 775 Intel P45 ATX Intel Motherboard
Item #: N82E16813128358

RAM G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 1066 Dual Channel RAM
Item #: N82E16820231166

Processor CPU Intel Core2 Quad Q9400 2.66GHz LGA 775 95W Quad-Core CPU
Item #: N82E16819115131

HSF fan 92mm size ARCTIC COOLING Freezer 7 Pro 92mm CPU Cooler
Item #: N82E16835186134

I think that's the entire list.
a b ) Power supply
a c 229 V Motherboard
January 18, 2009 9:24:46 PM

Quote:
Are you saying that it's normal for the cpu fan to NOT spin immediately and that it spins later on in a few seconds?
Yes with that motherboard (and probably with a few others as well).

Your PSU is a bit below recommendations for your video card, but that doesn't cause your issue.

As far as I'm concerned, you have a PSU problem, a memory problem or something is shorting out. Test it outside of the case to make sure the motherboard, CPU and one DIMM works (you can put the motherboard on a non-conductive surface). It will at least eliminate a short with the case.
January 18, 2009 9:50:20 PM

I kept the power on the longest time about 8-10 seconds, you're saying the cpu fan wouldn't turn on in 10 seconds?

That seems like it would damage the cpu.
a b ) Power supply
a c 229 V Motherboard
January 18, 2009 10:27:29 PM

It can't damage the CPU. The fan failed to start on mine and each time the system ran for several minutes before it would shutdown. I could boot Windows Server 2008 and download and install patches before it would shutdown. The CPU obviously wasn't very busy and that's why it took me a few cycles before I decided to open the case to analyse why it shutdown. Then I saw that the fan had failed. It's nearly impossible to destroy a Core 2 CPU if the heat sink is installed.

EDIT: On mine, it takes 4 seconds for the fan to start spinning.
January 18, 2009 10:33:40 PM

So If I simply booted into the BIOS are you saying that the HSF fan wouldn't come on for many minutes? I've never seen or used a computer who's cpu fan didn't come on immediately.

Also it does BUMP an inch of the fan immediately and then no spinning, seems fishy it would bump and it be normal....?
a b ) Power supply
a c 229 V Motherboard
January 18, 2009 11:28:45 PM

It moves very slightly on power up (what you call a bump) and 4 seconds later it starts spinning. You need to identify why your system doesn't work, but it has nothing to do with the lack of an 8-pin CPU connector from the PSU. The 4-pin is plenty for your CPU.
January 19, 2009 12:38:00 AM

I said earlier that I left it on for 8-10 seconds which should have been enough right?
a b ) Power supply
a c 229 V Motherboard
January 19, 2009 12:58:47 AM

And what happens if you leave it on for a lot longer, e.g., for 30 seconds or one minute? 8-10 seconds isn't enough to know if the system will POST or not.
January 19, 2009 1:46:49 AM

You're probably right but I barely could afford this build to begin with and risking the $284 CPU is scaring the crap out of me now.

I should be getting the 8-pin adapter in the morning, perhaps we could do some disccusing about this when I try that out?

I'm a tad frightened about blowing this $284 cpu is all.

thanks
a b ) Power supply
a c 229 V Motherboard
January 19, 2009 2:24:44 AM

If the heat sink is installed properly, you can't blow it.
January 19, 2009 3:27:02 AM

oK, My friend and I will try your Idea sometime tomorrow and report back to you how it turned out.

thanks
!