8GB memory update

Hi there

Have an unstable mac. So I ran hardware test 6 times in a row.

One of the tests gave me the error code: 4MEM/9/40000000: 0xa9f2ac18

It's supposed the be bad RAM. So I will use the opportunity to upgrade my memory to 8 GB.

What is the manufacturer recommended by Apple. Do want to buy a from low quality manufacturer.

This much i can see about the specs:

- Double Data Rate Small Outline Dual Inline Memory Module (DDR3) format

-30mm (1.18 inch)

- 2 GB or 4 GB

- 204-pin

- PC3-8500 DDR3 1066 MHz type RAM

Thank you so much.

NB: Sorry if a similar answer have been posted before. Cannot search the forum with success.