GeForce 8600m GT; signs of failure?

[Project Alice]

Hey all,
I know that most the 8600m GT's fail and need replacing. I have this 2008 15" MBP I am trying to install Monterey on, and it has done a couple weird things.

The laptop came with Mac OS 10.10.5 installed, and aside from being slow it seemed to work fine. I am at the point in the Monterey installer where it rebooted and is no longer booted from the installer drive. The screen has flickered many times, and it hung for about an hour on "Less than a minute remaining...". I rebooted, and there were some weird anomalies and I couldn't get into the boot picker. I rebooted a few more times that resulted in just a black screen.

I finally got it booted again and now its installing again. The screen randomly flashes every few minutes. Think this is a faulty 8600? if it is; @dosdude1 do you still replace these?

 

[Project Alice]

I’ve booted into Snow Leopard and am running openmark. It seems to be fine? I’d imagine a benchmark like this would cause a failed 8600m to act up would it not?


Edit: was posted on mobile, fixed the image being posted mid-sentence.

 

[dosdude1]

It almost certainly is. If you can boot an OS, check the PCIe Lane Width for the GPU in Graphics/Displays section of System Profiler. If it shows anything less than X16, it's failing. But based on what you described, that is most likely the case. I do indeed still perform these GPU replacements, in fact I just finished one up yesterday, and have two more on the way to do. Also one thing to check also is to see if there's a green dot sticker on the RAM slots. Just open the RAM door and it will be visible. If the green dot is there, that indicates it has a board with the revised chipset installed, done under warranty repair back in the day.

 

[Project Alice]

It almost certainly is. If you can boot an OS, check the PCIe Lane Width for the GPU in Graphics/Displays section of System Profiler. If it shows anything less than X16, it's failing.

Well then.. there’s my answer. Snow Leopard’s system profiler showed it as being X1 which I thought was weird.

 

[SecretSquirrel]

Hey all,
I know that most the 8600m GT's fail and need replacing. I have this 2008 15" MBP I am trying to install Monterey on, and it has done a couple weird things.

The laptop came with Mac OS 10.10.5 installed, and aside from being slow it seemed to work fine. I am at the point in the Monterey installer where it rebooted and is no longer booted from the installer drive. The screen has flickered many times, and it hung for about an hour on "Less than a minute remaining...". I rebooted, and there were some weird anaomies and I couldn't get into the boot picker. I rebooted a few more times that resulted in just a black screen.

I finally got it booted again and now its installing again. The screen radomly flashes every few minutes. Think this is a faulty 8600? if it is; @dosdude1 do you still replace these?

I thought Catalina on one of these was ambitious. How are you installing Monterey? Let us know how you get on!

 

[Project Alice]

I thought Catalina on one of these was ambitious. How are you installing Monterey? Let us know how you get on!

GPU is bad, I'm lucky it even booted SL.

Anyways, this is how you get Monterey working on just about anything. Though this was my first attempt at using it on a non-metal GPU mac.
I do have a 17" 2008 MBP that seems to be okay, boots SL and shows the GPU as being x16 like it should. It doesn't have a drive though. I just ordered an SSD for it, that should be here in a couple days. Assuming it's GPU works, I hope to have it booting Snow Leopard and Monterey.