Broken 9400M GPU in Late 2008 MBP

[USER_CRYPT0]

Hey all,
I have an old Macbook Pro Late 2008 (5,1) with dual GPU. One of these GPUs is broken. Nvidia 9400M is default graphic card, so my mac keeps rebooting and I can boot it only in Safe mode. Is there any way to set 9600M gpu as default? By terminal or something? I've been trying with gfx card status but it didin't work. It's very important to me because I don't want to buy new motherboard.

Ps. sorry for my English

 

[chscag]

Welcome to our forums.

It's very likely that the nVidia 9400M has failed. The integrated GPU (Intel) remains working.

There is a way to permentantly turn off the nVidia but it does entail quite a bit of work.

Here is one thread from MacRumors that may help. There are others also. You need to do some googling to find one that you can use. Keep in mind that your MacBook Pro is vintage and now going on 13 years old.

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forums.macrumors.com

 

[Quinten]

The 9400m is likely not the culprit but the 9600m gt is. During boot up the Mac utilizes the discrete gpu in this case the 9600m gt and if this one is broken the Mac wil not bootup. To disable the 9600m gt during bootup enter single user mode by starting up with CMD+S and enter this command:

nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00

Brightness control may no longer work but the system now should work fine.