Cold boot problem after updating BIOS Z97X-Gaming 5

[Leopardi]

I was dumb and updated my F5 bios to F7 just because I wanted it to be newer. It introduced the PCI-E Gen 3 bug, which causes PCI-E1.1 style performance with terrible stutter and 50% FPS on some boots, and even totally failed cold boots (only fans spin but nothing else happens) requiring pressing reset to boot up fully. Gen 2 setting works flawlessly, but obviously it is eating up my 1080 Ti performance a little.

Specs:
Z97X-Gaming 5
2x8GB Kingston DDR3 1866MHz
Palit 1080 Ti Jetstream
Crucial MX100 & MX300 500GB SSD's
Seasonic P-660 platinum

I have
*changed the power reset kit on case with a spare part
*changed CMOS battery
*removed soundcard from the PCI-E X1/X4 slot
*flashed F6 and F8b bioses
*reset BIOS settings
*tried changing the PCI-E DMI Link Speed setting
*reinstalled Windows 10 a few times (was a long shot, since problem behaviour shows up in BIOS already)

So, any ideas? There quite a few mentions about this Gen 3 PCI-E cold boot bug around the internet when you dig up, but Gigabyte support acted like this isn't reality, and didn't care about a motherboard that is older than 2 years.

[Leopardi]

I guess theres nothing to try? 

[shadowsports]

I guess theres nothing to try? 

Have you checked to see if there is an updated BIOS for your video card?  This is the only thing left you have control of short of you swapping your Devil's Canyon CPU for a 5th gen Broadwell.  I wouldn't invest any more money in this platform if it were me.

[absic]

Hi there,

there is the F8a (beta) BIOS that you could try.

You can download it from TweakTown here: https://forums.tweaktown.com/gigabyte/28441-gigabyte-beta-bios.html

[shadowsports]

Hi there,

there is the F8a (beta) BIOS that you could try.

You can download it from TweakTown here: https://forums.tweaktown.com/gigabyte/28441-gigabyte-beta-bios.html

@Leopardi...

There you go.  Another possible solution from "King Absic"

[Leopardi]

Update on this: boot problems disappeared by overclocking memory to 2133MHz and setting voltage to 1.56v.

Dunno why overclocking memory enables PCI-E 3.0 but it did.

[shadowsports]

Update on this: boot problems disappeared by overclocking memory to 2133MHz and setting voltage to 1.56v.

Dunno why overclocking memory enables PCI-E 3.0 but it did.

This is certainly good news. 

The issue is likely related to the memory's SPD detect in conjunction with the CPU, and not due to PCI-e spec.

[Leopardi]

Update on this: boot problems disappeared by overclocking memory to 2133MHz and setting voltage to 1.56v.

Dunno why overclocking memory enables PCI-E 3.0 but it did.

This is certainly good news. 

The issue is likely related to the memory's SPD detect in conjunction with the CPU, and not due to PCI-e spec.

Manually setting the timings to as in default spec to 10-11-10-30@1866MHz doesn't work even at the higher 1.56v voltage. Though I wonder if the voltage setting even works, "Profile DDR voltage" in BIOS is greyed out at 1.5v and HWiNFO reports 1.5v - While the DRAM voltage setting is set to 1.56v in BIOS.

The Auto settings at 2133MHz are reporting 13-13-12-35.