They were Nvidia failures due to a manufacturing defect. My 15” 2008 Nvidia 8600-equipped MBP was repaired out of warranty (for free) for this issue.

All MacBook Pros from late 2007 to 2010 used Nvidia GPUs, not AMD.

Search “nvidia 8600 fail” to read more.

I had 15” MBP, maybe a 2010, that was dual GPU with an Nvidia that was definitely a problem.

D700s dying in the trash can Mac Pros cost me (and many others) a lot of time and money.