RAM pour Mac Pro mid 2010

Hello,

What kind of RAM can I buy for my Mac Pro mid 2010 (2x 4-core processors 4x 2GB DDR3 ECC 1066 MHz). I am still (happily) running snow leopard but wanted to purchase some additional RAM (32 or 64go) before upgrading to Sierra.

Unfortunately no ref are longer available on the Crucial website, my local apple store redirected me to a local computer shop which was unable to help either.

Would you have a suggestion of where I could purchase this specific type of RAM or indicate to me an alternative reference that I could find more easily and that could make my Mac Pro happy?

Thank you so much in advance!!

Mac Pro

Model Identifier: MacPro5,1

Processor Name: Quad-Core Intel Xeon

Processor Speed: 2.4 GHz

Number Of Processors: 2

Total Number Of Cores: 8

L2 Cache (per core): 256 KB

L3 Cache (per processor): 12 MB

Memory: 8 GB