Graphics card causing motherboard to cut out

[ljtsge]

i bought a z420 motherboard and a e5 2670  to go into the board. when i try to boot it up without a graphics card it powers the board. but when i have my r7 260x installed it does not. at first i thought it was becasue of my 400w power supply so upgraded it to a 650w but still to no avail. im thinking it could be a bios thing but im not sure

[BeemerBiker]

I had similar problem on Z400.  Make sure you do NOT have "compute" enabled in the PCI express BIOS setup for any of the slots.  The last manual here  mentions putting the graphics card in the "primary" graphics slot.  I think that is the one closest to the CPU.  That 650 watt power supply is more than sufficient.  I had to mod the power cables to use a standard ATX power supply on my Z400s

There is a recent BIOS update (2019)

https://support.hp.com/us-en/drivers/selfservice/hp-z420-workstation/5225033

[edit]  I just re-read your post.  That motherboard does not have on-board graphics so that r7 is the only graphics card you have?  Do you have another graphics card even an old PCI card you can try?  Even if both PCIe slots were set to "compute" the motherboard should still power up.  If it is not powering up with the card inserted then there is some other problem.

[ljtsge]

is there any way to update the bios without a video adapter?

i have never seen the bios on this board so i dont know if that option is enabled

[BeemerBiker]

I think you posted before I finished editing my reply.

Does the motherboard power up when the r7 card is installed?

Have you got another card you can try?

My symptom was the z400 powered up but there was no display until I managed to remove the "compute" from the PCI express settings.  Even a CMOS reset did not remove the "compute"

SANITY CHECK:  Is the 6 pin PCIe power cable connected to the r7 card?

[ljtsge]

this is what happened when i tried to boot it with the gpu installed 

[content removed]

as i said before am i able to access the bios without a screen with just a keyboard and change what i need without a screen

yes the 6 pin is connected 

[Prométhée]

hi

maybe you can answer this question, @BeemerBiker  @ljtsge   I have a doubt

The graphics card, and can only be used with a bios type uefy?
and the motherboard, does it support the bios Uefi?
if not, it could explain your problem

and this

Supports:
● PCIe Gen3 (PCIe3) bus speeds; can support two PCIe Gen3 graphics cards in
PCIe3 x16 slots
● Up to 225 W graphics or compute card in the primary graphics slot (600 W PSU)
● Up to 75 W graphics in primary slot (400 W PSU)
● A second graphics card in the second PCIe3 x16 slot
● Third and fourth 2D graphics cards in additional PCIe2 slots
● Combined power consumption of all cards not to exceed 270 W (subject to overall
system power limitations and configuration restrictions) (600 W PSU)
● Combined power consumption of all cards not to exceed 75 W (subject to overall
system power limitations and configuration restrictions) (400 W PSU

[ljtsge]

update

my motherboard is now cutting off without the gpu plugged in

[BeemerBiker]

I suspect there is some other problem but there a few things yet to be tried.

1 - Look carefully at the socket to ensure the r7 is properly seated.

2 - try the other graphics slot

I just went over to eBay and looked at a Z420 motherboard.  It appears the x4 slots have an open back side.  If so you can try another of the x4 slots even though your r7 is a full x16 length.  Just make sure the extra connectors that extend out the back of the socket do not touch any metal parts on the motherboard.

My Z400 did not have open backside x4 sockets so I had to use an x1 to x16 "riser" adapter to get the video to work.

I suspect the problem is not the bios as my system powered up just fine and yours is shutting down.  

Can you borrow another video board even an old pci type for testing?

[BeemerBiker]

---

@ljtsge wrote:

update

my motherboard is now cutting off without the gpu plugged in

---

Not good

Anytime you insert or remove a PCIe card, memory stick, etc be sure the system is turned off using the switch at the back or unplugged from wall if no switch.

Questions for my own curiosity

1 - How did you get that video on Youtube to be stabalized?  The few that I post you can tell I am shaking / cannot hold the camera perfectly still.  

2 - did you use an HP 600watt or use the adapters as described here ?

https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/HP-z420-motherboar...

[ljtsge]

1. i think its an iphone auto stabliser (im a very shaky person as well)

2.  im using an 24 pin to 18 pin adapter