AMD Motherboards - X399 Taichi lack of primary PCI-e select

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X399 Taichi lack of primary PCI-e select

Printed From: ASRock.com
Category: Technical Support
Forum Name: AMD Motherboards
Forum Description: Question about ASRock AMD motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=6708
Printed Date: 21 May 2024 at 11:16pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: X399 Taichi lack of primary PCI-e select

Posted By: spot4me
Subject: X399 Taichi lack of primary PCI-e select
Date Posted: 24 Nov 2017 at 11:34am

" rel="nofollow - I have two VGA, one is GTX 1080, placed on the first 16x slot, near to the CPU and the other is GTX 1030 placed on the seconday 16x slot.

GTX 1030 is the only card connected to display and is the only card used to visualize anything on the screen.

GTX 1080 is used only for off-screen computations and rendering. It is never connected to a display.

The reason 1080 is on the first 16x slot, and the 1030 on the second - is because of air flow and cooling conditions in the case. If I switch locations of both cards, the cooling of the heavy loaded 1080 will be insufficient.

It seems that BIOS selects the first VGA, on the first 16x slot, although it is not connected to any monitor.

If I want to enter BIOS and see what is happening there, I have to connect 1080 to the monitor. The problem is that I don't see any part of the booting process which is problematic until you see the Win10 login screen, where the OS detects which card is connected to the monitor.

So, is it normal behavior that no screen except PCIE1 slot?

Replies:

Posted By: ASRock_TSD
Date Posted: 24 Nov 2017 at 12:23pm

Dear spot4me,

Greetings, this is ASRock TSD.

For this question, we build a system with 2xGTX 1060 VGAs card to simulate your configuration.

In order to get better performance, we install two VGA cards on PCIe1 & PCIe4 slot to get x16/x16 bandwidth. And system will only output the screen on PCIE1.

Note: 4 x PCI Express 3.0 x16 Slots (PCIE1/PCIE2/PCIE4/PCIE5: single at x16 (PCIE1); dual at x16 (PCIE1) / x16 (PCIE4); triple at x16 (PCIE1) / x8 (PCIE2) / x16 (PCIE4); quad at x16 (PCIE1) / x8 (PCIE2) / x16 (PCIE4) / x8 (PCIE5))

Based on our test result, we can confirm that the primary graphic is set at the first PCIe slot (PCIE1) so there's no graphic output on PCIE4 unless the system is post into OS.

Thanks!

All the best,

ASRock TSD

Posted By: starmax
Date Posted: 24 Feb 2018 at 3:19am

I have the same problem, it would be great if you could make the primary VGA slot a BIOS option.

Posted By: pebenito
Date Posted: 18 Jan 2019 at 9:58pm

I repeat this request. I'm looking to build a VM server with a pass-through GPU on one of the VMs. I only need to put a low-end graphics card for the primary display (for the host system), since it will only have a text console. If the primary display is always PCIE1, then I would be wasting an x16 slot by putting a low-end card there.

To make it more concrete, I'm planning:
1. host graphics card (requires x1 slot)
2. passthrough graphics card (requires x16 slot)
3. Intel I350 SR-IOV network adapter (requires x4 slot)
4. AsRock Ultra Quad M.2 (requires x16 slot)

So if you look at this list, I need 2 full x16 slots, but I can't do that if the host graphics card has to be in PCIE1.