GPU prevents PC from boot

[MightyM0use]

Hello,

my problem is that PC is consistently stops during post if gpu is intalled.

The gpu in question is saphire r9 380, motherboards are gigabyte ga-31m-es2l and biostar hi-fi z87w. 

 

What i tested:

PC boots from iGPU if GPU is not installed.

If GPU is installed PC stops during POST.( on both motherboards)

GPU has switch to change vBIOS to UEFI, I tried switching it between boot atempts, but nothing changes.

I tried get POST codes with PCI POST-card and it seems PC stops consistenly on POST code 2b for both Award Modular BIOS v6.00PG and biostar UEFI 2.3.1: PI 1.2.

I tried to check voltage on GPU board and found that Vcore, Vmem and memory controller voltages looks ok as well as 0.95v on pcie rail.

Pcie to ground resistance onrx and tx lines consistent as well. Pcie capacitors also ok.

I cant fin any problem with GPU board visualy as well.

I also tried flash another vBIOS version, but again it changed nothing.

 

Maybe you have expirienced similar problem or have any ideas what causing this. 

I would be grateful for any help or suggestions regarding my problem.