So, how does it work

and still it does not work

Has been used intensively in my Dell laptop for 6 months and does not trigger any errors on memtest+ 86 (I test my computer on a monthly basis).

It's cheaper than the Apple's one, does the same job, and works like a charm

But it does not work in Macbook Late 2009 or after

The architecture does not support the hardware of the rest of the computer.

If it does fail which is rare, but happens, expect quite a bit of a headache and hours wasted figuring out what went wrong

CORSAIR definitely offers a great deal and even though it says "laptop" memory, the iMac handles it well and so does the RAM

dont blame amazon for price changes :D