MacBook Pro Mid-2009 (5'5) RAM Upgrade Issue

[Wowamit]

I have a MacBook Pro Mid-2009 with 2GB of RAM (1xGB). I had recently decided to upgrade it to 8GB after checking the allowed capacity on Apple support website.

I ordered 2x4GB of 1066GHz RAM and installed both the RAM sticks. The machine did not boot with continuous 3 beeps.

I removed the RAM sticks and installed them with 1x1GB of the old stick and it works fine. (So a total of 5GB). I have tested this combination at both the slots with both the new 4GB RAM sticks. They work fine with the 1GB stick.

However they do not work together. Both the sticks are exact same model, I bought them together.

Is there something I am missing or doing incorrectly?

 

[ScoobyMcDoo]

When you boot with 1 stick of 1G and 1 stick of 4G did you go into the OS to verify that it did indeed recognize a total of 5G of RAM?

 

[Wowamit]

Yes, I did. It shows 5GB of RAM.

 

[drindia2014]

Same issue with Mid 2010 Macbook pro

I have mid 2010 13 " macbook pro 2.4 Ghz 4Gb RAM. I purchased transcend 8Gb (2x4Gb) ddr3 1066 cl7 RAM. When I install both new RAM, macbook do not start (screen remains off) but when I use one native ram (2Gb) and one new (4Gb) it works and shows 6 Gb ram. I follow instructions for RAM installation but unable to upgrade to 8 Gb RAM. Plz suggest solution.
Thanks a lot in advance