Intel Motherboards : [Z68 Extreme4] HD7850 -> RX480 upgrade woes

Author: Fa1lson
Subject: [Z68 Extreme4] HD7850 -> RX480 upgrade woes
Posted: 22 Feb 2017 at 6:29am

Thanks for your thoughts, Moderator Group members! I seem to have come to the right place

parsec wrote: It seems you were using Windows 7 when you inserted the RX 480, correct?

Yes, this has been the only OS in play so far (tho' I will try a win10 install in the next few hours as it's probably the easiest OS to use for this exploratory work, given my lack of SP1 win7 install media and the hassle of slipstreaming or what-have-you).

You lost me when you said this in your first post: Restore all BIOS settings to their former values with the exception of BIOS -> [Boot] -> [PCI ROM Priority]. This setting (which has two values - the default 'Legacy ROM', and 'EFI Compatible ROM') seems to completely determine whether the monitor lights up or not. The last sentence is correct if you were using Windows 7 and did not have a UEFI booting Windows 7 installation, which I assume you did not. I'm sure you had no monitor signal when you set it to EFI Compatible ROM, correct?

Yes, no monitor signal when 'EFI Compatible ROM' = [PCI ROM Priority]. I've also confirmed that I do not have a UEFI booting win7 installation (by running 'bcdedit /enum', which shows in the 'Windows Boot Loader' section that path = ...\winload.exe).

Question, why did you try using the PCI ROM Priority, EFI Compatible ROM setting? Were you using that setting with your other video card?

I was indeed using it with the other card, and the HD5830 I used before that, IIRC. (However, I've just tried booting the other card with the 'Legacy ROM' setting, and all is well.) Now, exactly why I changed this setting from its default value when I first installed the m/b is something only my 2011 self (who deeply pondered each and every UEFI setting, as you do) can answer... In any case, I initially sought to get the RX480 going by making as few changes as possible to UEFI settings (hence my restoration-to-former-values approach).

It was sheer luck that I was able to quickly identify this particular setting as culprit. The [Boot] screen was the last I needed to visit when restoring UEFI settings to their former values. I was confused by what I saw in it, tho', so did a 'save and exit' (in case its content changed as a result of settings I'd already altered) before changing its default values. Following the subsequent reboot, I changed the [Boot] screen settings (including [PCI ROM Priority]) to their former values, 'saved and exited', and stared glumly for a few seconds at the blank screen that resulted.

While your new video card may have a VBIOS that supports EFI, your Windows installation must also support EFI booting. If it doesn't, particularly with Windows 7, you cannot use that setting.

I can't even get a _monitor_signal_ using that setting, so I'm OK with using 'Legacy ROM' = [PCI ROM Priority]

I'm glad that updating the UEFI is not at this point compulsory. I really must get around to overclocking that CPU...

I've also learned that some RX480-based cards have a wee hardware switch on them to choose between... legacy or EFI VBIOS, I think? Alas, mine does not seem to.

Will report results of win10 install attempt in a few hours all being well...