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SOLVED Motherboard won't post with video card in PCI-E x16 slot 1

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Tech Tweaker

Member
Joined
Dec 14, 2010
I've got an odd problem.

I have a board (DFI LP nF4 SLI-DR) here that will not pass POST if I have the video card inserted in PCI-E x16 slot 1 and it gives a video error POST beep, but if I use the secondary slot (Slot 3) with the same video card all is fine and the system will POST and run normally (aside from the issue of having to run the card in the secondary slot). It doesn't matter whether I have the video set up for normal mode or SLI mode, the system won't post with the video card in the primary PCI-E x16 slot either way.

Problem here is that if I run my video card in slot 3 I am limited to x2 bandwidth at normal settings, and the only way I can get anything higher than that is to enable SLI and then I can only get it up to x8 but cannot get full x16 bandwidth because only slot 1 can do that.

This is some sort of hardware fault or short as far as I can tell, as when I run the card in a different slot all is fine, and putting the video card in slot 1 gives the same result as running the system with no video card inserted at all. It's like the board doesn't even detect anything in PCI-E x16 slot 1 even when a card is inserted.

Anyone ever had similar issues and/or have any suggestions for a solution?
 
have you checked in the BIOS to make sure it's checked for PCIe 1. It could be that card is PCIe 1.0 and not compatable with PCIe 2.0 or, you could have a bad PCIe slot. i've seen it happen when pulling/putting in mem sticks, it some how casue the slot to get shorted out. Could be same thing with your PCIe slot.

Have you tried a differnt video card in the slot? sounds like you may need to RMA the board if you can
 
i'm pretty sure the slots on the motherboard are 1.0 and 2.0 slots should be backwards compatable with older cards any way
 
have you checked in the BIOS to make sure it's checked for PCIe 1. It could be that card is PCIe 1.0 and not compatible with PCIe 2.0 or, you could have a bad PCIe slot. i've seen it happen when pulling/putting in mem sticks, it some how casue the slot to get shorted out. Could be same thing with your PCIe slot.

There's no way to select different slots in the bios of this board that I can see.

Have you tried a different video card in the slot? sounds like you may need to RMA the board if you can

That shouldn't be an issue, I've tried PCI-E x16 1.0 and 2.0 cards with the same results.

I've probably tried 3-5 different video cards, at a minimum I've used an nVidia 6600GT (1.0), 8400GS (1.0), a 9800GT (2.0), and an ATi X600 Pro (1.0).

Well, unfortunately the board is from around 2005-2006 IIRC, so it's well beyond the warranty I'd imagine. Plus I believe DFI has completely stopped supporting their consumer products and only focuses on server products now.

i'm pretty sure the slots on the motherboard are 1.0 and 2.0 slots should be backwards compatible with older cards any way

Yes, these should be 1.0 slots.

I don't see why that would be a problem either. Normally you can run a PCI-E 2.0 card in a 1.0 slot without any problem, or a 1.0 card in a 2.0 slot and so on. I run a 2.0 card in a 1.0 slot in my backup computer normally and it has no issue with it.
 
Try cleaning the PCIe slot and resetting CMOS for kicks and giggles.

Yeah, I've tried that multiple times too.

Cleaned the slot with compressed air several times. Yesterday I had the CMOS battery and BIOS chip completely off the board, so they were fairly well drained of power.
 
Fixed it! :attn:

I gave that little PCI-Express port a good working over with the heat gun to re-flow the solder joints.

She runs like a champ now. I have only done some initial testing to get it to output video of the initial boot-up screens and going into the bios to configure the settings there, and then going into a stripped-down install of XP and running a few programs. I have verified in CPU-Z that it is running at the full x16 bandwidth on the PCI-e x16 slot, so that's good.

I actually had to re-flow the solder twice before it started working right. Once yesterday just to get the board to POST and output video at all and another today to get the primary x16 slot working. I think I just didn't get it hot enough the first time around to melt and re-flow the solder in that one area.

Still not sure what would have caused the initial issue though, as the board is in fine physical condition with no signs of any damaged or broken components.:shrug:

I only wish it hadn't taken me so long to get to the point where I could try this, I was skeptical of putting a full desktop motherboard into an oven though and didn't want to risk melting any of the plastic components. I especially didn't want to try this one in an oven, since I had money invested in it and didn't want to make it even worse.
 
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