Strange Biostar TB250-BTC+ Video card issue

[Malbrosia]

I have 3 1080 ti running on a Biostar TB250-BTC+

One is a GB Gaming OC 11G
One if a MSI Gaming X 11G
One is a GB Aorus

These all work fine together.

I added a forth card, another MSI Gaming X 11G and the BIOS would not read it.

I spent hours swapping out risers, cables, checking settings, reinstalling drivers, updating the bios and in the end realized that it was the card itself and everything else was fine.

I thought at first the MB did not like having a 4th card, but then I put an older GTX 970 as the 4th card (using the same risers, connections, etc) and the BIOS and Windows read it.

Then I took that out and put the 2nd MSI back in and again the BIOS, nor Windows would detect it.

I then took out the other MSI Gaming X 11G card, thinking it may be a conflict of two exact cards, and only left the non-working MSI in the rig and yet the BIOS would still not read it.

The 2nd MSI card is fine. I've been using on my Gaming rig without any problems, but I cannot figure why it won't read with this Biostar MB.

I do run my monitor off the integrated graphics connector if that makes any difference.

Has anyone experienced anything like this or know what the problem and solution may be?

Thanks

[Malbrosia]

So I switched motherboards, and am using an ASUS Prime Z270-P.

I have running on it four 1080 tis, and my older GTX 970 and they all run fine.  The second MSI 1080 TI will light up, fans will spin, but neither the BIOS nor Windows will read or detect it even if it is in isolation or when plugged in the regular PCI x 16 slot.

Yet, it works perfectly fine when I put it in my my main gaming machine using the PCIe x 16 slot.  My main gaming machine sports a Gigabyte Gaming 3 AB350 MB.

It does not appear to be a PSU or riser issue.  I run two power supplies on the mining rig and have tested different cables and have used both PSUs, but keep coming up with the same frustrating result.

It is almost as if this cards knows it's going to be mining away for eons and refuses to play ball on the mining rig and wants to stay put on a nice comfy part-time gaming machine.

I am really stumped as I cannot figure out why this second MSI card will not be read by two different mobo bios' and subsequently windows. 

If it would not work at all, then I could easily just RMA it, but the card does work and I'm not sure if they will just send me back the card if it also works on their test machines.

Just because I am clueless at this point, I'm going to throw this out.  Is it possible that either the harddrive (I'm using an Intel SSD), or RAM (Ballistix brand 2400 Mhz 8 GB) or CPU (Celeron 3930) could conflict or cause issues here?  These are the only things I have not switched out yet.  I could try using the RAM from my gaming machine, but I don't have another CPU or SSD lying around and prefer not to spend more money just to find out. 

If anyone can help, I'd be willing to make a donation to the person who helps me figure out and solve the problem.

Thanks.

[MrTDHP]

Try enabling 4G decoding in the bios setting?

[Malbrosia]

Yes, 4G encoding was enabled on both motherboards. 

[MrTDHP]

Hmm if it's not even detected in BIOS then it should be not driver/Windows issue. Did you say it's not even detected in BIOS when you unplug all other cards and only have this stubborn card directly into the x16 slot?

[Malbrosia]

Hmm if it's not even detected in BIOS then it should be not driver/Windows issue. Did you say it's not even detected in BIOS when you unplug all other cards and only have this stubborn card directly into the x16 slot?

Yes, I removed all other cards and only used this one MSI card.  It still would not work.  It is quite strange how it will load up on one motherboard (Gigabyte), but not two others (Biostar and Asus).  I have never seen anything like this before. 

All my other video cards (another MSI, Asus, and GB) work just fine and it's simple plug and play and detect.

I switched out the RAM and still have the same problem.  The only thing I have not tried to switch is the CPU and SSD as I do not have a couple of those lying around and do not want to spend more money just to find out they are not the problem.

I have spent so many hours trying to figure this out that I am about to give up and just RMA the card.

[MrTDHP]

Ya that's super weird. If it is detected in BIOS then it's a different story, since many people didn't bother checking the BIOS and simply thought it is not working/not detected while it's actually just Windows issue which takes super long time to install the driver.

[yoyome]

I'm assuming Mining mode is enabled in bios? (not sure if btc+ has that option like btc pro)
Also try switching PCI from auto to gen 1 or gen 2.
Does the card power on, fans spin? tried a different pci slot?