2009 macbook pro 17" ram upgrade ?

If your computer more fully identifies with the specifications here, from http://mactracker.ca database

it would be considered a MacBook Pro (17-inch, Mid-2010) using MacBook/Pro 6.1 model identifier:

And if confirmed elsewhere (see specs + serial number lookup at everymac.com) then Max RAM is 8GB:

Built-in Memory None

Maximum Memory 8.0 GB

Memory Slots 2 - 204-pin PC3-8500 (1066 MHz) DDR3 SO-DIMM

• MacBook Pro: How to remove or install memory - Apple Support

One of the most reputable vendors of upgrade memory and drives for Macs is OWC macsales:

• Upgrades for 2008-2010 Apple MacBook and MacBook Pro Unibody Models:

http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_Pro/Upgrade/DDR3

Works with Model Identifiers: MacBook5,1; MacBookPro5,1; MacBookPro5,2;
MacBookPro5,3; MacBookPro5,4; MacBookPro5,5; MacBookPro6,1;
MacBookPro6,2 & MacBookPro7,1
Where do I find this? | Your Model ID not listed? Click Here!

*NOTE: these models require the most current EFI version as well as Mac OS X v10.6.6

or later. Please visit this link for more information

So the identification of your computer is essential, as would be matching the correct parts

in exacting terms since Macs are rather picky when it comes to upgrade RAM quality spec.

Good luck & happy computing! 🙂