GA-Z97X-Gaming 5 & F6 bios issues, is it possible to downgrade?

[deus2k3]

Hi All,
I'm using GA-Z97X-Gaming 5 with 4790k CPU and 750Ti NVIDIA card. Due to that fact that my NVIDIA card support only HDMI 1.2 I also use internal 4600 GPU (HDMI 1.4 ) for bitstreaming HD audio to audio receiver. I has to keep "Internal video" enabled is BIOS to make this feature work.


After upgrading my BIOS from F5 to F6 version my 4600 GPU became very unstable in windows 8.1. After 5-10 minutes from boot Windows starts to show "Intel (HD) Video Driver crashed and was reset" message and next the whole system became unstable and freeze.


I've tried to reinstall Win 8.1 from scratch, upgrade BIOS to F7a and installed a lot of Intel video drivers but the issue still occurs. The only way to make system stable is to turn Internal video off.

Questions:

1) Does anybody know the way to fix this?
2) Is it possible to downgrade BIOS back to F5? There is some kind of protection in F6 version and it's not possible to install old BIOS version over it.

[shadowsports]

The only real need for upgrade to F6 would be if you were planning to get a Broadwell CPU.  And there really isn't enough of a performance increase to justify the expense. You've got yourself in a mess because you cannot downgrade to F5.

You have two options. 
Upgrade your video card to one that support HDMI 1.4.  (best option)
Upgrade your CPU to Broadwell (Iris 6200 graphics ) HDMI 1.4 support

I'd go for a video card.  Way more bang for your buck...  unless you can get a Broadwell cpu handed to you. 

[deus2k3]

I found a solution: I used 2x4 DDR-1333 RAM from my old computer, after setting RAM clock to 1600 system became pretty stable. Seems like new BIOS versions prefers memory clock speed >= 1600 Mhz.

[shadowsports]

So were you using non QVL ram or overclocking? 

[deus2k3]

According to vendor specs this MB supports DDR-3 1333 Kingston modules: http://download.gigabyte.eu/FileList/Memory/mb_memory_ga-z97x-gaming5.pdf. Actually I have to overclock it to 1600 to make system stable on new BIOS version.

Update: the reason of failure was "auto" mode for RAM clock multiplier in BIOS. I've set it to "16" for 1600 or "13" for 1333 and system became stable. Looks like those I'm turning off some hardware throttling scheme.

[shadowsports]

Thanks for the reply.  Ya some memory even when properly detected by SPD doesn't work right with XMP profiles.  You aren't losing any performance using a 16 multiplier and the CPU can still do turbo boost if "k" series.  Glad you found a stable setting.