Author: parsec
Subject: [Z68 Extreme4] HD7850 -> RX480 upgrade woes
Posted: 22 Feb 2017 at 9:46am

Fa1lson wrote:

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...

If you are fine with using the Legacy ROM setting, then there is no reason to install Windows again, unless you simply want to use Windows 10.

Forgot to tell you some mandatory UEFI installation techniques that even Windows 10 will require. In case you aren't aware of this...

Whatever Win 10 installation media you use, before the installation starts check the boot order and find the installation media. It should be the only other drive connected to (or powered up) in the PC besides the target OS drive. You should find an entry for the Win 10 installation media that looks something like this: "UEFI: <installation media name>". You need to select the boot order entry with the "UEFI:" prefix, which causes a UEFI booting Windows installation.

Not sure if you are using an HDD or an SSD as the Windows 10 drive. I assume the SSD. No idea if any or all HDDs support using the EFI boot loader.

EDIT: See Additional Information I added at the bottom of this post, related to the following paragraph.

If you want a full blown UEFI booting Windows installation, the CSM option must be set to Disabled. That of course requires the video source to support the UEFI GOP protocol, which does not seem to be the case, so you can't set CSM to Disabled. What you can do with CSM enabled, is set the CSM sub-option, Launch Storage OpROM Policy option to UEFI Only. That will cause the OS drive to be GPT formatted, and have four partitions created by the Windows installer, including a legacy MBR partition. Any or all of this is not required, but selecting the "UEFI:" entry for the Windows installation media is required.

Regarding choosing the PCI ROM Priority setting of UEFI ROM with your previous video card, the result of that was nothing. The chances of the HD 7850 supporting UEFI/GOP are very small, so that setting was simply ignored, if not changed to Legacy automatically. That you had the video display failure with the new video card implies that the new card does support UEFI/GOP, but your Windows 7 installation of course did not, resulting in no signal to the monitor. Of course we are going by what you tell us, so it is impossible to know what else might be going on, so this is just guess work.

About updating the UEFI, just to check, you have the Z68 Extreme4, not the Z68 Extreme4 Gen3 board, correct?

Given that, the latest UEFI/BIOS version (a Beta version, L2.21A) is from 2013, so I don't see that version as helping in general with a very current video card. But in checking into that, I noticed something else, which caused me to check your board's manual.

Additional Information

Since the manuals are rarely updated to match the UEFI/BIOS updates, I see nothing about any PCI ROM Priority option, or related options. I'm not saying they are not there, just that I cannot determine exactly what they are doing. Also, after reading the description of the L2.21A Beta UEFI/BIOS version, which adds Windows 8 support, no doubt including Secure Boot, I imagine the UEFI booting related settings were changed. I believe they would be similar to the next generation chipset boards, like the Z77 Extreme4, which I still have. The UEFI booting/CSM settings have not changed since the Z77 boards (no reason to do so), but I now realize your board's UEFI/BIOS version does not have a CSM setting, at least with the 1.50 version, and likely only with the L2.21A Beta version.

Bottom line, none of this is really significant, just use the Legacy ROM setting, it only matters during POST anyway.

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