Question 980ti in 2008 mac problems

[adam.edward.palmer]

So i have a 980ti that i tried in my 2008 mac pro. I got 2 mini 6 pin to regular 8 pin cables in order to power the thing (i wont be putting the card under much load anyway so dont worry about that). When i conect everything up, the mac powers on, does the start up sound, but never displays any video out of the card, with the display saying no signal. The fans spin on the card the whole time with lights above the power connectors indicating that its powered.
Any ideas on whats happening?

(Ps. the card that came with the mac displays picture so its not the macs fault and the 980ti does work)

 

[velocityg4]

It can't talk with the Mac's EFI. Meaning that MacOS cannot use the card even in generic mode until the drivers for it load. You need to install nVidia Web Drivers for Mac first. Using your old card. Then you can install the 980 Ti and boot.

You will get a black screen then until the drivers load during the boot process. Keep your old card around. You'll need it if you ever have to do any diagnostics or other boot options which require the screen to work pre-boot. You'll also need the old GPU after an OS update to install the appropriate nVidia Web Driver.

Note that nVidia Web Drivers only work up to macOS High Sierra. While nVidia has updated them for Mojave. Apple has decided not to sign them for whatever reason and nVidia won't release them without Apple's approval. So, Mac Pro users are either stuck with High Sierra using nVidia GPU or they have to switch to AMD GPU.

The drivers are available from nVidia. Download for your version of Mac OS X. You won't find anything for the GeForce 900 series. You look for

• Quadro
• Quadro Series
• Quadro K5000 for Mac
• Show all operating system (then select your version of OS X 10.10 minimum for 900 series)
• Optimal Driver for Enterprise (ODE)
• Your language

https://www.nvidia.com/Download/index.aspx

If you also want CUDA drivers for Mac. Find the latest version for your version of Mac OS X.
https://www.nvidia.com/object/mac-driver-archive.html

More detailed info

How to Install a Standard PC Nvidia GTX GPU in a Mac Pro: Using an unflashed GTX TITAN X, 980 Ti, 980, 970 or 960 in a Mac Pro | The Ultimate Mac Pro Community

Guide to using unflashed Nvidia GTX 9XX GPUs in a classic Mac Pro. In this guide we will show you how to save money, time, and keep your workflow rock

create.pro

Mods, as the op is asking for help in getting an unsupported GPU working in an official Mac product not a hackintosh. I assume the above falls within acceptable forum posting rules.

 

[adam.edward.palmer]

It can't talk with the Mac's EFI. Meaning that MacOS cannot use the card even in generic mode until the drivers for it load. You need to install nVidia Web Drivers for Mac first. Using your old card. Then you can install the 980 Ti and boot.

You will get a black screen then until the drivers load during the boot process. Keep your old card around. You'll need it if you ever have to do any diagnostics or other boot options which require the screen to work pre-boot. You'll also need the old GPU after an OS update to install the appropriate nVidia Web Driver.

Note that nVidia Web Drivers only work up to macOS High Sierra. While nVidia has updated them for Mojave. Apple has decided not to sign them for whatever reason and nVidia won't release them without Apple's approval. So, Mac Pro users are either stuck with High Sierra using nVidia GPU or they have to switch to AMD GPU.

The drivers are available from nVidia. Download for your version of Mac OS X. You won't find anything for the GeForce 900 series. You look for

• Quadro
• Quadro Series
• Quadro K5000 for Mac
• Show all operating system (then select your version of OS X 10.10 minimum for 900 series)
• Optimal Driver for Enterprise (ODE)
• Your language

https://www.nvidia.com/Download/index.aspx

If you also want CUDA drivers for Mac. Find the latest version for your version of Mac OS X.
https://www.nvidia.com/object/mac-driver-archive.html

More detailed info

How to Install a Standard PC Nvidia GTX GPU in a Mac Pro: Using an unflashed GTX TITAN X, 980 Ti, 980, 970 or 960 in a Mac Pro | The Ultimate Mac Pro Community

Guide to using unflashed Nvidia GTX 9XX GPUs in a classic Mac Pro. In this guide we will show you how to save money, time, and keep your workflow rock

create.pro

Mods, as the op is asking for help in getting an unsupported GPU working in an official Mac product not a hackintosh. I assume the above falls within acceptable forum posting rules.

Thanks so much for the detailed reply. What ypu are saying does make sense, and i will give it a go. 🙂
Also, the mac that i am using is stuck on El capitan due to its age and im not interested on forcing the newest version of mac os onto it.