MSI Z-107A Pro Gaming Windows Freezes

[xMines]

Hey Guys,

I'm building my new Rig now but I have problems first of all here are the specs of my rig:

RAM: 4GB DDR4
Motherboard: MSI Z-107A Pro Gaming
CPU: Intel G4400
GPUs: 2x RX480 8GB (so far, waiting for the rest)
HDD: 250GB SATA
OS: Win10 64-Bit
PSU: 750W EVGA, I connected a single Powercable to each GPU, didn't use multiple GPUs on one power line.

I installed Win10 64-Bit, the drive is MBR not GPT. I have read that GPT is a must is that right?
System powers up and it's running so far properly until I run Claymore Miner (newest Version), the System freezes and the screen gets black. In device manager I can see both GPUs, also all drivers are installed.
I tried BIOS Version 1.7 which made Above-4G disappear. Currently I tried 7984v1E (newest Version) with the following settings:

UEFI+ Legacy is set,

Windows Os settings:
Win10 support is "off" (when I change it to "on" it doesn't boot, also when I change each of the 5 settings to "disabled" it doesn't boot anymore)
Win7 is "Enabled"
MSI fastboot "disabled "
fast boot "disabled"
secure boot "disabled"


Settings/Advanced:
PEG0 is Auto
PCI Latency is 32Bit
Above-4G is Disabled
!There is no PEG1!
-System is starting properly-

What I tried so far:
Changing PEG0 to "Gen1/Gen2/Gen3"
in combination with Above-4G "enabled"
-System doesn't boot anymore- also not in combination with the windows OS settings.

I also tried to use the internal GPU which didn't solve it.
What I'll try today: install windows in GPT drive and set Motherboard to UEFI only before, is this setting important?

I read each post about the Z107a Motherboards so far, nothing worked for me. Hope you guys can help.

Best Regards,
xmines

[666mrga999]

You need GPT formatted windows with full UEFI above 4G decoding and PCIE to gen 1.

[xMines]

You need GPT formatted windows with full UEFI above 4G decoding and PCIE to gen 1.

thanks I'll give it a try. So installation in UEFI+LEGACY and then change to UEFI only. I'll keep you updated. Where anybody able to run another GPU in the M2 slot?

BR xMines

[xMines]

But why is the system crashing with default settings?

[xMines]

You need GPT formatted windows with full UEFI above 4G decoding and PCIE to gen 1.

I'll check today, yesterday I checked SimplesmineOS which were working with 4g decoding disabled and PCIE Auto only. How does SimplemineOS work it's no GPT and no UEFI? Also my system crashes after mining for a few minutes, I think it's cause of the GPU BIOS or Driverversion how should I solve this? When I increase the Fanspeed to min.100% in SimplemineOS OC Settings it's stable but only with one card  
There are also questionmarks about EthOS.

BR xMines