X99 Extreme4 - can't get 5th GPU working

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   Hello,
I recently built a system (mining rig) with an x99 Extreme4 Mobo. It has been running great for a few weeks with 4 MSI RX470 4GB's hooked up (1 on board and 3 connected via USB powered risers - in PCIe slots 1, 3, 4 &5).  2 days ago I hooked up my new Sapphire Nitro+ RX 470 8GB (to slot #2 via USB powered riser, which is the PCIe 2.0 x16 slot) , but after doing so, could not get the rig to even reach the boot screen.  When powering on, begins the start process but after a few seconds, it stalls out and restarts again.  It just continues in this cycle until I power it off.  I tried several times with different connectors, etc but had the same result every time.

I am hoping someone here can suggest a way to fix this issue.  Here are my system details:

- X99 Extreme4
- i7-6800K
- Windows 7 Pro x64
- Rosewill 1000W Plat PSU

Note that I have plenty of headroom power-wise. Before adding the 5th GPU, my system is only pulling 600-650W.

Edited by GabryRox - 24 Oct 2016 at 5:03am

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GabryRox Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 24 Oct 2016 Status: Offline Points: 5	Post Options Post Reply Quote GabryRox Report Post Thanks(0) Quote Reply Topic: X99 Extreme4 - can't get 5th GPU working Posted: 24 Oct 2016 at 4:53am
	Hello, I recently built a system (mining rig) with an x99 Extreme4 Mobo. It has been running great for a few weeks with 4 MSI RX470 4GB's hooked up (1 on board and 3 connected via USB powered risers - in PCIe slots 1, 3, 4 &5). 2 days ago I hooked up my new Sapphire Nitro+ RX 470 8GB (to slot #2 via USB powered riser, which is the PCIe 2.0 x16 slot) , but after doing so, could not get the rig to even reach the boot screen. When powering on, begins the start process but after a few seconds, it stalls out and restarts again. It just continues in this cycle until I power it off. I tried several times with different connectors, etc but had the same result every time. I am hoping someone here can suggest a way to fix this issue. Here are my system details: - X99 Extreme4 - i7-6800K - Windows 7 Pro x64 - Rosewill 1000W Plat PSU Note that I have plenty of headroom power-wise. Before adding the 5th GPU, my system is only pulling 600-650W. Edited by GabryRox - 24 Oct 2016 at 5:03am

parsec Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 04 May 2015 Location: USA Status: Offline Points: 4996	Post Options Post Reply Quote parsec Report Post Thanks(0) Quote Reply Posted: 24 Oct 2016 at 1:42pm
	You may have headroom from your PSU, but is it being delivered to your video cards? The USB powered risers, are they able to provide 12V power to the cards? USB power is only 5 Volts. Do you have a cable connected to the four pin PCIe power connector on your board? It's located above the PCIE1 slot, next to the memory slots. The PCIE2 slot uses PCIe 2.0 lanes provided by the X99 chipset. The other slots use the PCIe 3.0 lanes provided by the CPU. Maybe there is a problem with them working together.


GabryRox Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 24 Oct 2016 Status: Offline Points: 5	Post Options Post Reply Quote GabryRox Report Post Thanks(0) Quote Reply Posted: 24 Oct 2016 at 3:00pm
	Thanks for the feedback. To address your first questions about sufficient power going to this 5th GPU... yes, in addition the USB connection from PCIe slot to x16 riser, I have molex power routed to it, as well as the 8 pin (6+2), both coming directly from the PSU. This is exactly how the other 3 off-board GPUs are set up and they work fine. So, I don't think it's a power issue... but you may be onto something regarding the 2.0 slot/x99 chipset issue. This also may be the reason that when I initially plugged in one of my MSI GPUs into this slot early on in my build, it was only getting 20% the mining hash-rate the other slots were getting. I know that some Mobos simply cannot support more than 4 GPUs but this being a higher-end Mobo, I was truly hoping that wouldn't be the case. Is there something in the BIOS that I can check/validate/change to address this issue?

GabryRox Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 24 Oct 2016 Status: Offline Points: 5	Post Options Post Reply Quote GabryRox Report Post Thanks(0) Quote Reply Posted: 26 Oct 2016 at 1:07am
	Any other ideas on this issue? I was really hoping a $200 Mobo would be able to handle 5 GPUs (since there are several sub-$100 boards that can handle 6). Possibly something in the BIOS configuration? I am at a stand-still at this point so any help would be highly appreciated.

Xaltar Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 16 May 2015 Location: Europe Status: Offline Points: 27623	Post Options Post Reply Quote Xaltar Report Post Thanks(0) Quote Reply Posted: 26 Oct 2016 at 3:09am
	Any more than 4 GPUs is always a logistical nightmare. Contrary to popular thought, higher end boards do not always have an easier time accommodating 5+ GPUs, the problem lies in resources. On say an H110 board with 6 PCIe slots, only 1 is x16, another x4 and all the rest are x1. Add to that the fact that there are very few (comparatively) additional features on the chipset and it is easy to see why multi GPUs would do well there. With high end boards you have multiple "extras" that need resources like the M.2 slots, extra SATA and mSATA ports, dual gigabit LAN and the list keeps on going the more high end you go. All of this needs resources that are now no longer available for a multiple GPU setup. In the end you need a way to allocate sufficient resources to enable you to use a fifth GPU. The only way I can see to do that is to talk with Tech Support directly and ask them to help you out with some BIOS tweaks (update). I know they have helped users with issues like yours in the past so I don't see why they wouldn't be up for the challenge


u53rn4m3 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 14 Jun 2017 Status: Offline Points: 1	Post Options Post Reply Quote u53rn4m3 Report Post Thanks(0) Quote Reply Posted: 14 Jun 2017 at 8:54pm
	Did you ever figure out a way to get the 5th GPU working? Exact same problem here. Thanks

majonezas Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 18 Dec 2017 Location: lithiania Status: Offline Points: 1	Post Options Post Reply Quote majonezas Report Post Thanks(0) Quote Reply Posted: 18 Dec 2017 at 2:41am
	i've enabled above 4g decoding in bios and now mining with 5 nvidias. now thinking of getting m2 to pcie adapter and trying 6 cards