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Additional PCI-E x16 Power to Mobo - Should I connect it?

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February 1, 2008 3:18:25 PM

I finally got to set up my new build this week, which includes a Gigabyte P35 DS4 rev 2.0 motherboard. In the manual, it says to connect a 4pin molex power connector to the PCI-E x16 power connector on the motherboard if running two video cards. Since I was only running one 8800GTS 512 (G92) I didn't connect it.

But after installing the video driver CD, on re-boot the Nvidia Sentinel program said the card was receiving insufficient power and was going to throttle the card back to compensate. I'm running power to the card itself directly from my Corsair 620HX PSU via one of the modular PCI-E power cables, so I was quite surprised to see the message. I double checked the connection, and tried a different power cable - same result.

I updated the Nvidia driver to the most recent release, and I stopped getting the message, but I'm not convinced it's fixed for good. I did some Google searches, and it appears this is a rather common problem right now. It has something to do with the timings between the PSU and the newer G92 video cards. Has anyone else run across this problem?

So this long winded background story leads me to my simple question. Should I run a molex power cable to the motherboard's PCI-E power connector even if I'm only running one video card? I don't know if doing this could give TOO MUCH power to the PCI-E x16 slot if only running one card. I'm kind of a noob when it comes to how power works in computers.
February 1, 2008 3:28:31 PM

yeh - connect power connector to the motherboard - its what its there for......
February 1, 2008 3:34:51 PM

You shouldn't be concerned with providing too much power. You should only be concerend if the voltages are correct. The device itself will draw what it needs. But incorrect voltage can damage stuff.
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February 1, 2008 4:29:22 PM

llnyc is correct.
February 1, 2008 4:48:03 PM

Agreed. No device will draw more than it needs unless it is being fed a higher voltage than it is supposed to have. Just use something to double check your voltages. If the gigabyte Mobo came with the EasyTune program that my Gigabyte came with you can use that to check your voltages. All voltages should be within +/- 5% at the worst prefereably never outside +/- 3%.
a b V Motherboard
February 1, 2008 4:50:54 PM

Please list your specs, power supply may be insufficient for your system.
February 1, 2008 5:19:21 PM

evongugg said:
Please list your specs, power supply may be insufficient for your system.


I highly doubt it, but here are the essentials:

CPU: E8400 (running at stock speed/voltage for now)
Mobo: Gigabyte P35 DS4 rev 2.0
RAM: 2x 1GB Crucial Ballistix DDR2-800 (letting the BIOS run auto timings and voltage for now)
GPU: EVGA 8800GTS 512 (G92)
PSU: Corsair 620HX
Drives: 2 Seagate Barracudas (non-RAID), IDE DVD Reader/Writer
Fans: 5 120mm (4 case, 1 CPU)

The 620HX should be way more than I need. The main reason I bought it over the 520HX was for the possibility of future upgrades.
a b V Motherboard
February 4, 2008 11:47:03 AM

Yes your power supply is more than enough.
a b V Motherboard
February 4, 2008 12:27:11 PM

Jaywill said:
I finally got to set up my new build this week, which includes a Gigabyte P35 DS4 rev 2.0 motherboard. In the manual, it says to connect a 4pin molex power connector to the PCI-E x16 power connector on the motherboard if running two video cards. Since I was only running one 8800GTS 512 (G92) I didn't connect it.

But after installing the video driver CD, on re-boot the Nvidia Sentinel program said the card was receiving insufficient power and was going to throttle the card back to compensate. I'm running power to the card itself directly from my Corsair 620HX PSU via one of the modular PCI-E power cables, so I was quite surprised to see the message. I double checked the connection, and tried a different power cable - same result.

I updated the Nvidia driver to the most recent release, and I stopped getting the message, but I'm not convinced it's fixed for good. I did some Google searches, and it appears this is a rather common problem right now. It has something to do with the timings between the PSU and the newer G92 video cards. Has anyone else run across this problem?

So this long winded background story leads me to my simple question. Should I run a molex power cable to the motherboard's PCI-E power connector even if I'm only running one video card? I don't know if doing this could give TOO MUCH power to the PCI-E x16 slot if only running one card. I'm kind of a noob when it comes to how power works in computers.


Gigabyte recommends that users check for the latest bios after installing a mobo,as there MIGHT be changed/updates ,also some gbyte mobo's have a 6 pin connector on the mobo,for the cpu only tho...
asus has the same thing on my present mobo a 4 pin molex for sli only ,don't plan on going that way tho..:) )


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