X99 Extreme4 - can't get 5th GPU working
Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=3647
Printed Date: 02 Aug 2025 at 1:06am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: X99 Extreme4 - can't get 5th GPU working
Posted By: GabryRox
Subject: X99 Extreme4 - can't get 5th GPU working
Date Posted: 24 Oct 2016 at 4:53am
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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.
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Replies:
Posted By: parsec
Date Posted: 24 Oct 2016 at 1:42pm
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" rel="nofollow - 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. ------------- http://valid.x86.fr/48rujh" rel="nofollow"> 
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Posted By: GabryRox
Date Posted: 24 Oct 2016 at 3:00pm
| " rel="nofollow - 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? |
Posted By: GabryRox
Date Posted: 26 Oct 2016 at 1:07am
| " rel="nofollow - 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. |
Posted By: Xaltar
Date Posted: 26 Oct 2016 at 3:09am
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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  ------------- 
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Posted By: u53rn4m3
Date Posted: 14 Jun 2017 at 8:54pm
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" rel="nofollow - Did you ever figure out a way to get the 5th GPU working? Exact same problem here. Thanks
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Posted By: majonezas
Date 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 |