Very Strange. Have You Seen this Before?

[ocnewb]

Im building a new machine
Here are the Specs

Asus P5N-E SLI mobo
2GB Cas5 DDR2 6400
E6400
XFX 7900GS

I got the machine all put together, boot up with just the power and monitor plugged in. Posts fine every thing looks good. I plug in my keyboard to get into bios(which is the latest), turn the pc on..no video. Check the card check the memory, still no video. I unplug the Keyboard(PS2) and still nothing. Power off the pc again, boot up with no keyboard and bam.. It posts. This was the last time it would post. I tried my KB again with no luck. I have tried different memory, with no luck. I put the vid card in another machine, it works fine, as does the mem.

Now here is the kicker,
here is a link to my mobo: Here

If you look between the two PCI-E Slots you will see a red chip. On one side it says for Single Video Card(yes i made sure it was in tight and clean). You flip it over and plug it in for Dual Vid cards. So For giggles i flipped it, so its now plugged in to run dual vid cards. And BAM! Every thing works fine with just a single card, posts with kb, can get into bios. Everything looks normal. My questiion is will this affect the card in any way(will it run 8x instead of 16x?). Does any1 know why it wont run in Single card mode?

 

[niz]

Maybe there's a problem in the 8 lanes of your video card that get ignored when you set your motherboard video slots to 2x8 instead of 1x16. And maybe the reason that your videocard works in the other motherboard fine is that it is actually only an 8 lane slot even though it is a pci-e 16 connector. This is true of many of the first pci-e motherboards. It was only relatively recently that any motherboard had full 16 lanes on x16 pci-e slots.

 

[human_error]

You didn't plug the video card into vid card slot 2, which would be disabled in single card mode, but enabled in dual slot mode did you? If you did, then that could cause trouble. Slot 1 should be the blue one on the board, however it can be changed in the BIOS i believe.

That's all I could think of...

 

[ocnewb]

Maybe there's a problem in the 8 lanes of your video card that get ignored when you set your motherboard video slots to 2x8 instead of 1x16. And maybe the reason that your videocard works in the other motherboard fine is that it is actually only an 8 lane slot even though it is a pci-e 16 connector. This is true of many of the first pci-e motherboards. It was only relatively recently that any motherboard had full 16 lanes on x16 pci-e slots.

The other machine I tested the vid card in is a Gigabyte DS3. I tried both PCI-E slots with the chip in Single Card Mode.

 

[human_error]

Hmm... could mean that you vid controller chip is dead in single card mode, but at least it works in dual mode.

 

[ocnewb]

In dual mode tho is the card runing in 8x and not 16x? Or will it run at 16x till i add another card?

Either way I will probably be returning this board.

By the way, ASUS tech support...Worst ever..

 

[human_error]

First i'd as asus if you can get a replacement chip - it could just be that that's dead, but replacing the board will get you a new chip, so either way you'd have to wait for the pc to work.

I've not had the delights of ASUS tech support yet, my mobo from them was fine, hope they will allow you to replace the mobo with no probs.

 

[trixst4r]

wont cpu-z tell you if you are running at 8x or 16x?