Maximum card bus issues

Gintok

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Sep 19, 2009
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Long time reader first time poster :)

I'll try and keep this concise. I've been seeking help with a graphics card issue I've had. Basically I own a 790FX motherboard which allows me to run two ATI cards in a CrossFireX method at x16 each. I've only been running one card at a time to test each card (thankful I did) and have encountered problems.

I have the exact same graphics card for the CrossFire solution, as in I am using the same make and manufacturer (EAN/UPC barcode is the same at the back). Now get this. One of my 3870s which I bought can only run at x8 speed. It was correctly seated and plugged in with a quality PSU.

When I bought the card it looked like it had been opened before as the drivers CDs appeared to have been opened, a molex cable had been taken out of the plastic and there was no static bag, rather a bubble wrap bag. Still as it was the first card, I bought it. When the second card (again remember same make and model) arrived, it came with a static bag in completely mint condition which leads me to believe this one could have been returned.

And now back to the problem. I run the "mint" condition card which I am sure is brand new and it runs at x16 speed. The card that I suspect was used can only run at x8. I'm using the same slot of testing both cards and have not changed any components or settings. Both cards are the same cards, using the same BIOS and so on.

It's really annoying because I tend to find that although the card I suspect is used and faulty can pass a 3Dmark loop is still can often cause issues in Left4Dead and general browsing, but it's random and can take 20 minutes to appear. I might be playing when suddenly the screen cuts out and graphics hangs, 15 seconds later all good.

The mint condition 3870 card has NO issue what so ever. I'm keen to do an RMA but seeing as the retailer isn't keen on doing one plus seeing they were fairly shady in the first place, is there any way I can fix this myself?

Is it possible for a card to be fixed from x8 to go back to x16 or is this some kind of issue that is unfixable on my end? I'm guessing someone had the same issue beforehand and returned it to the retailer.
 
Just to be clear:

You run Card_A by itself and it runs x16. You run Card_B by itself in the same slot and it runs x8.

There's no way I know to fix that problem on your end.

What do you use to tell you x16 or x8? And what is the make and model of your mobo please?
 

Gintok

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To the first question yes. I did this to eliminate any variable by using the SAME slot in BOTH cases and as they are the same card I found it weird.

My motherboard is a Gigabyte MA790FX-UD5P. It uses a 790FX chipset so regardless BOTH slots will run at x16.
 
Not that I know of. It's not like x8 or x16 are switch selectable on the video card.

The spec calls for the vid card to negotiate with the slot to resolve 4, 8, or 16 electrical and PCIe V1.0, 1.1, 2.0. Your card isn't doing that in a slot that obviously can negotiate well.
 

Gintok

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What I find weird is how a card that is designed to be x16 can go to x8 (keep in mind the slot allows for x16 and does work at x16 with the other 3870). Does overclocking a card damage it in such a way the bandwith/bus just goes "Can't do x16 anymore, I'll step down to x8"?
 

Gintok

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Chances are I'll probably get some refurb (I don't live in the US). I don't know what your experiences with RMA parts involves or if you've had to but in my experience, it's painful, overly long, the emphasis of blame is always put on the end user (IE me) and I end up getting some refurb which chances are could be worse.

What is it, rock and a hard place :p

PS: Now you know why I'm so keen to fix it myself :)
 
Not this time, you have proof.

"I have two of your cards, identical part and rev number. One operates correctly in my PC at x16. When I replace it with your second card, that card runs at x8. I can send you screen shots if necessary. I need an RMA for the second card."