Just plopped a crucial M4 128GB in my 1st gen Macbook and so far so good. Enabled TRIM without any hiccups and it is nice and fast. That being said, the 1.5Gbps limit is a real bummer. On my PC w/ SATA III I'm getting 3 to 4 times the performance as I am on the macbook. I guess I can't expect much for how old this guy is. The performance improvement is very much worth it though even if I am still wary about the whole TRIM issue.