Moderators carlo_67 Posted November 19, 2025 Moderators Share Posted November 19, 2025 Put the 4090 in the PCIe x16_1 slot Place the second GPU in the PCIe x16_3 x4 slot, but I doubt you'll have room at the bottom to insert it. sorry my english 1 Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted November 19, 2025 Author Supervisor Share Posted November 19, 2025 @khileare you sure that rx6600 is full working? have you tried it with other os? 1 Link to comment Share on other sites More sharing options...
khile Posted November 19, 2025 Share Posted November 19, 2025 26 minutes ago, fabiosun said: @khileare you sure that rx6600 is full working? have you tried it with other os? so moved to slot 3 on pci-e and still not seen by Mac but works fine in windows and I can mirror or set it as main display and it works fine Link to comment Share on other sites More sharing options...
Moderators carlo_67 Posted November 19, 2025 Moderators Share Posted November 19, 2025 Is the resize bar enabled in the BIOS? Also run a CMOS to force detection and reset the NVRAM on the Mac, reboot from Mac and see what the card says under Information/Graphics and Monitor. Basically, it should see it. I get an error without WhateverGreen.kext. however it is the 4090 that predominates the slots, you have to try to temporarily remove it and try only the 6600 in pcie 1, once the mac is started insert it in the device properties of Opencore and put the boot arg nv_disable, put them back as they are now and try to start 1 Link to comment Share on other sites More sharing options...
Muhammed Salah Posted November 20, 2025 Share Posted November 20, 2025 Please Update EFI Folder to support macos 26 installer Link to comment Share on other sites More sharing options...
khile Posted November 21, 2025 Share Posted November 21, 2025 so if i only have the 6600 in slot one the pc sees it no problem but as soon as i have the 4090 in any slot the 6600 is no longer seen i do have all the m.2 slots populated as well Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted November 21, 2025 Author Supervisor Share Posted November 21, 2025 i think your CPU lacks of some PCIE lanes... and this is a problem usually motherboard loose a nvme slot in your case seems differemnt 1 Link to comment Share on other sites More sharing options...
khile Posted November 22, 2025 Share Posted November 22, 2025 I'm overdue a cpu upgrade, might look at a 9950x as the cpu is quite old i have now Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted November 22, 2025 Author Supervisor Share Posted November 22, 2025 17 minutes ago, khile said: I'm overdue a cpu upgrade, might look at a 9950x as the cpu is quite old i have now you will gain a bit in performance and also a better thermal design 3 Link to comment Share on other sites More sharing options...
Muhammed Salah Posted December 23, 2025 Share Posted December 23, 2025 On 11/22/2025 at 6:40 PM, fabiosun said: you will gain a bit in performance and also a better thermal design hello i want efi working with macos 26.2 please Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted December 23, 2025 Author Supervisor Share Posted December 23, 2025 2 hours ago, Muhammed Salah said: hello i want efi working with macos 26.2 please @Muhammed Salahi would like peace in all the world 🙂 only joking!! put your exact hardware you desire a "working" EFI! Link to comment Share on other sites More sharing options...
Muhammed Salah Posted December 23, 2025 Share Posted December 23, 2025 32 minutes ago, fabiosun said: @Muhammed Salahi would like peace in all the world 🙂 only joking!! put your exact hardware you desire a "working" EFI! MB: ProArt x870E RAM: 32GB 6600 mhz GPU: Rx 6600XT i'am using now sequoia Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted December 23, 2025 Author Supervisor Share Posted December 23, 2025 31 minutes ago, Muhammed Salah said: MB: ProArt x870E RAM: 32GB 6600 mhz GPU: Rx 6600XT i'am using now sequoia Post your efi working with sequoia Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted December 23, 2025 Author Supervisor Share Posted December 23, 2025 @Muhammed Salahyou can also check in originate post , i added Tahoe support in my previous EFI if you post your sequia working one i could update yours 😉 Delete your serial to be safe Link to comment Share on other sites More sharing options...
Muhammed Salah Posted December 23, 2025 Share Posted December 23, 2025 6 hours ago, fabiosun said: Post your efi working with sequoia this current EFI EFI-ProArt-23-12-2025.zip Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted December 23, 2025 Author Supervisor Share Posted December 23, 2025 4 minutes ago, Muhammed Salah said: this current EFI EFI-ProArt-23-12-2025.zip 9.5 MB · 0 downloads Are you using a 6 core cpu? Link to comment Share on other sites More sharing options...
Supervisor fabiosun Posted December 23, 2025 Author Supervisor Share Posted December 23, 2025 EFI.zip this is your exact EFI updated for Tahoe whatevergreen updated patches updated usbmap.kext updated for tahoe * *here it seems you use two method for usb mapping (not good in my opinion) Also SMBIOS could be updated to MacPro7.1 (you use instead iMacPro1.1) also your core count is set to 6 it means you have a 6 cores cpu installed. Do You? EDIT: Also acpi ssdt section is a bit (too much) populated in my opinion Link to comment Share on other sites More sharing options...
Muhammed Salah Posted December 24, 2025 Share Posted December 24, 2025 13 hours ago, fabiosun said: EFI.zip 11.22 MB · 0 downloads this is your exact EFI updated for Tahoe whatevergreen updated patches updated usbmap.kext updated for tahoe * *here it seems you use two method for usb mapping (not good in my opinion) Also SMBIOS could be updated to MacPro7.1 (you use instead iMacPro1.1) also your core count is set to 6 it means you have a 6 cores cpu installed. Do You? EDIT: Also acpi ssdt section is a bit (too much) populated in my opinion thanks so much working very good Link to comment Share on other sites More sharing options...
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