XFX Invisible to OS .... ?

[BittBurger]

My setup:

1)  ASUS 280x on 16x plug
2)  ASUS 280x on 1x plug
3)  Sapphire 280x on 16x plug

All three are detected by OS and mining software, and work great.

4)  XFX 280x .... i put on the remaining 1x plug.  

OS doesn't recognize it (not in device manager at all), and doesn't mine, though its spinning just fine, powered, etc.

I have an ASRock Extreme4 motherboard.  

How can I get this last GPU to be detected by the OS?  

I tried putting in the drivers CD for the XFX.  Catalyst popped up like it always does and began installing stuff all over again.  I have no idea if it actually detected the XFX.  No idea if it was installing anything specifically for the XFX. 

Help!

[nachius]

have you tried the xfx in one of the known working slots?

If it works in another slot I would try one of the working cards in the 1x slot the xfx card currently occupies if this is on a riser test the riser with another known working card as well.  Also if one of the 1x slots work you should not need to jumper, but this could also be tested: https://bitcointalk.org/index.php?topic=36061.0

[BittBurger]

have you tried the xfx in one of the known working slots?

If it works in another slot I would try one of the working cards in the 1x slot the xfx card currently occupies if this is on a riser test the riser with another known working card as well.  Also if one of the 1x slots work you should not need to jumper, but this could also be tested: https://bitcointalk.org/index.php?topic=36061.0

Okay.   I completely switched all the risers and the cards.

Then installed each card one by one.

This time the XFX (second in line) detected and installed and runs fine.

Apparently the problem is - the fourth GPU - no matter what it is - no matter where its plugged in - and no matter which riser it uses .... doesn't get detected by the motherboard.

At least that's my assumption.  They're all in different positions now.

The 4th GPU installed is an ASUS that was working fine before, in a slot that was working fine before, using a riser that was working fine before.

Yet in Device Manager, only 3 Display Adapters are detected.

Is there some setting that allows more than 3 GPU's to be detected?  That's the only thing I can think of.

-BB-

[BittBurger]

Update:  Solved.

Problem was this:   I couldn't use both 1x slots.   I can only use one of them.

So this worked:   GPU 1: 16x ..... GPU 2:  16x ..... GPU 3:  16x..... GPU 4:  1x

Basically pulled one GPU from a 1x and put it into a 16x.

Then the system detected it.