I have a Macbook pro 4,1 early 2008.
It's a great machine for surfing while the TV is on, but it's starting to act strange.
These screenshots are both of a google sheet -- same one a few minutes apart.
I can see two possibilities:
A: My GPU is dying, and doesn't work in certain modes.
B: I've got a bad memory stick.
How do I diagnose which?