MP 1,1-5,1 Mac Pro 5,1 with Pulse RX 580 DisplayPort boot issue

[kinless]

Howdy fellow Mac Pro nerds. Scrounged through these forums but couldn't find anything on the exact issue I'm having...maybe someone who has more knowledge than I can help point me in the right direction:

Mac Pro 5,1, latest 144.0.0.0, Mojave 10.14.6 (not using OpenCore or anything like that). Dual monitor setup with primary using DisplayPort, secondary using HDMI.

I purchased a "boot screen" Sapphire Pulse RX 580 8GB from DQupgrade (eBay). The card mostly works but there's one annoying hiccup. During macOS startup while using a DisplayPort monitor (either port), after the boot cycle is finished the screen goes blank then infinitely cycles between "Not Connected" and "Connecting" but never gets anywhere. Just prior to this I notice little horizontal pink line artifacts on the screen then the fans suddenly stop on the card. The infinite cycling issue also happens when waking the computer from sleep.

The workaround is to manually unplug and replug the DP cable from the card, which then brings up the macOS screen. (Sometimes it takes several attempts of unplugging/replugging to get it to work.) I have to do this after each restart/boot/wake-from-sleep into macOS.

This issue doesn't appear when using the HDMI ports. Also no issues with DisplayPort when booting natively into Windows via Boot Camp. Native boot picker using DP works fine as advertised. And of course my current GeForce GTX680 works fine using the same DP cable. It's only booting/waking into macOS via DP on the RX 580 when the issue surfaces. I've done SMC and PRAM resets which hasn't seemed to help at all. I don't know if it's a momentary power surge, or something in the startup process that's borking the DP handshake.

My first mistake was probably not buying directly from MVC, but their lack of response to my repeated email inquiries made me leery of making any purchase. My GeForce GTX 680 also came from DQupgrade, which I flashed myself and it's worked flawlessly the last few years, so I figured the RX 580 would be an easy decision. DQ has offered a full refund if I can't figure out this issue, so I'm not sweating that part. But I'd love to keep this card as I'm planning to purchase the upcoming Dell U3824DW (38" 3840x1600 ultra-wide) so need a card that can handle it.

Any ideas before I return this card? Thanks all!

 

[kinless]

Just to follow up, I bought some DP 1.4 and HDMI 2.1 cables from Monoprice to rule out connection issues. Primary monitor still goes black during boot/wake using DP so no dice there. But with the extra HDMI cable, my dual-monitor setup is now using both HDMI ports which all shows fine on boot/wake and seems to be the workaround for now.

I'd rather be using DP but we'll see how the incoming ultra-wide monitor fares with it...

 

[h9826790]

My suggestion is just return the card.

GTX680 Mac EFI UGA is coming form EVGA, that's a reliable manufacture with all the required info directly from Apple.

RX580's Mac EFI UGA is from MVC. He did a great job to make it work, however, extremely hard to make it as flawless as the GTX680 Mac EFI UGA.

Also, AFAIK, many people simply use hardware dumper to extra the MVC RX580 ROM (which may be developed from a MSI RX580 at the very beginning), then cross flash it to pretty much any RX580 (reference card, Sapphire PLUSE / NITRO+, XFX...). Even the card can boot, but the VBIOS part itself may be not 100% compatible at the very beginning.

Anyway, there is no need to buy any flashed card anymore. Just flash your Mac, then a RX580 with factory UEFI GOP ROM can show boot screen on the cMP.

https://forums.macrumors.com/threads/pre-opencore-gop-support-for-efi-era-imacs-and-mac-pros.2378942/page-17?post=32137842#post-32137842

 

[kinless]

Anyway, there is no need to buy any flashed card anymore. Just flash your Mac, then a RX580 with factory UEFI GOP ROM can show boot screen on the cMP.

Thank you sir. Been following that thread now and again but the ROM flash process always seemed intimidating (I'm not a super low-level techie). Thought I would try the hands-off approach first but looks like if I want to make this work I'll just have to hold my nose and dive in. Probably not as complicated as it looks.

How would I know if an RX580 I want to purchase has the factory UEFI GOP on it? Is it just an unflashed PC card?

 

[h9826790]

Thank you sir. Been following that thread now and again but the ROM flash process always seemed intimidating (I'm not a super low-level techie). Thought I would try the hands-off approach first but looks like if I want to make this work I'll just have to hold my nose and dive in. Probably not as complicated as it looks.

How would I know if an RX580 I want to purchase has the factory UEFI GOP on it? Is it just an unflashed PC card?

Most "unflashed" cards are OK. Some of them may shipped with VBIOS but not UEFI GOP.

However, it's so easy to download UEFI GOP ROM for RX580 on the net now (e.g. from TechPowerUp. Or just ask the card's manufacture to send you one). Therefore, in general, for modern grahpic card, there is no need to worry if the card is shipped with UEFI GOP.

Also, there are generic UEFI GOP avail. You can always make your own UEFI GOP ROM for your card. Just like the old days what we did to the GTX680 / HD7950.