[SOLVED] Old Motherboard and New AMD Graphic Card is a no-go. Nvidia Fine.

clutchc

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I was doing a little bottleneck experiment with some ancient builds (of which I have too many of), and I discovered that my Asus P7P55D-E LX (1156) board won't work with any RX-5xxx series AMD cards. Yet it works fine with the RX-5xx series and older cards. It also has no issue with any GTX 16xx/RTX 20xx cards and older. I haven't tried any newer Nvidia cards yet because I don't have any. The RX-5xxx cards produce the POST display at boot, but that's as far as it gets when W10 or any install disk/flash drive tries to load.

I guess the issue is the UEFI vs Legacy BIOS thing, yes? Did AMD make their newer cards non-legacy BIOS compliant?
 

delaro

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EVERY UEFI CARD HAS A CSM MODE

What is CSM mode?

The Compatibility Support Module (CSM) is a component of the UEFI firmware that provides legacy BIOS compatibility by emulating a BIOS environment, allowing legacy operating systems and some option ROMs that do not support UEFI to still be used.


Sometimes you have to reflash the firmware on the card to get the CSM mode to be seen on the older boards or do the workaround in that video. 🤷‍♂️ I've booted a RX 5700 all the way back onto a P45 board and even my MSI AM3 board which was super picky eventually worked with it.
 

delaro

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No, but there are a huge amount of driver conflicts that make initial and generic support fizzle out. You need to either be on a fresh install or boot off a secondary GPU then purge all graphics drivers and install the latest.
 
I disagree, I am nearly certain this is a UEFI/BIOS issue. My RX5700 would never work with my X58 sabertooth. Bios was fine, but past that was impossible, even to boot to just a linux USB.

Nvidia I believe is hit or miss anymore.

I have seen something similar work in reverse where an old GPU might not work with newer systems. My EVGA Classified GTX590 WILL NOT work with my Ryzen PC. It works fine in my 2500k and 990x system, but I just get a vga led in my am4 pc.
 

delaro

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All RX GPUs have a Hybrid setup, legacy video BIOS (vBIOS)and UEFI compressed graphics output protocol (GOP) ;) There is no reason they "CAN'T" work on both, some systems flake out on the hybrid bios though and you have to go the extra mile to get them working.
 

clutchc

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No, but there are a huge amount of driver conflicts that make initial and generic support fizzle out. You need to either be on a fresh install or boot off a secondary GPU then purge all graphics drivers and install the latest.
I tried a fresh boot from both DVD and flash drive. Soon as the POST screen is finished, the screen blacks out and there is no drive action or anything. Sits like that indefinitely. I even unplugged any internal drives.
 
I tried a fresh boot from both DVD and flash drive. Soon as the POST screen is finished, the screen blacks out and there is no drive action or anything. Sits like that indefinitely. I even unplugged any internal drives.
Basically the same thing my X58+RX5700 did.

Bios splash screen would pass, but then black screen. I did see a blinking curser in the corner of the screen though.

I have found that 5xx series GPUs will work fine with legacy boards, just like you said. Currently have an RX560 working on an LGA1156 OEM board without UEFI support. I previously tested my RX480 with a LGA775 board and it worked as well.

5700 Simply cannot do this. They are UEFI only. No legacy bios support at all.

View: https://youtu.be/fMF_SPcLL0Y


Here is the problem and the way to get around it.
 

delaro

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EVERY UEFI CARD HAS A CSM MODE

What is CSM mode?

The Compatibility Support Module (CSM) is a component of the UEFI firmware that provides legacy BIOS compatibility by emulating a BIOS environment, allowing legacy operating systems and some option ROMs that do not support UEFI to still be used.


Sometimes you have to reflash the firmware on the card to get the CSM mode to be seen on the older boards or do the workaround in that video. 🤷‍♂️ I've booted a RX 5700 all the way back onto a P45 board and even my MSI AM3 board which was super picky eventually worked with it.
 

clutchc

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I have some new information.
Going thru my notes, it appears I've had this same RX 5500 XT installed on another P55 board in back mid-2020. A Gigabyte P55A-UD3 with an i5-760. It worked just fine on that board. There goes my theory, and a nod to delaro. Looks like you are correct after all.

I don't have a 2nd PCIe x16 slot, tho. But, I wonder if an x1 to x16 riser would work?
 
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